diff --git a/src/doc/common/static/custom-furo.css b/src/doc/common/static/custom-furo.css
index fc76a3f7c0f..ae75c2b6383 100644
--- a/src/doc/common/static/custom-furo.css
+++ b/src/doc/common/static/custom-furo.css
@@ -21,3 +21,17 @@ a.pdf:hover {
   text-decoration: none;
 }
 
+/* Style for announcement banner */
+
+.announcement {
+    background: orange;
+}
+
+.announcement-content {
+    color: black;
+}
+
+.announcement-content a {
+    color: white;
+    text-decoration: none;
+}
diff --git a/src/doc/en/a_tour_of_sage/conf.py b/src/doc/en/a_tour_of_sage/conf.py
index a27957cb7f1..99940562965 100644
--- a/src/doc/en/a_tour_of_sage/conf.py
+++ b/src/doc/en/a_tour_of_sage/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/en/a_tour_of_sage",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/a_tour_of_sage', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/en/constructions/conf.py b/src/doc/en/constructions/conf.py
index a24d272be63..2797a22c271 100644
--- a/src/doc/en/constructions/conf.py
+++ b/src/doc/en/constructions/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/en/constructions",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/constructions', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/en/developer/conf.py b/src/doc/en/developer/conf.py
index e63fae87a99..9e5683fdb87 100644
--- a/src/doc/en/developer/conf.py
+++ b/src/doc/en/developer/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/en/developer",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/developer', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/en/faq/conf.py b/src/doc/en/faq/conf.py
index f6b3919b957..f3cb66c873d 100644
--- a/src/doc/en/faq/conf.py
+++ b/src/doc/en/faq/conf.py
@@ -24,7 +24,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/en/faq",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/faq', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/en/installation/conf.py b/src/doc/en/installation/conf.py
index 269093f1185..8d2b7694182 100644
--- a/src/doc/en/installation/conf.py
+++ b/src/doc/en/installation/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/en/installation",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/installation', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/en/prep/conf.py b/src/doc/en/prep/conf.py
index 22546f04af9..1540f1e4c21 100644
--- a/src/doc/en/prep/conf.py
+++ b/src/doc/en/prep/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/en/prep",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/prep', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/en/reference/conf.py b/src/doc/en/reference/conf.py
index 86aa0b05a81..9f3a4ec0364 100644
--- a/src/doc/en/reference/conf.py
+++ b/src/doc/en/reference/conf.py
@@ -25,6 +25,11 @@
 ref_src = os.path.join(SAGE_DOC_SRC, 'en', 'reference')
 ref_out = os.path.join(SAGE_DOC, 'html', 'en', 'reference')
 
+# Add a small edit button.
+html_theme_options.update({
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/reference/index.rst'),
+})
+
 # General information about the project.
 project = "Reference Manual"
 
diff --git a/src/doc/en/reference/conf_sub.py b/src/doc/en/reference/conf_sub.py
index b6f20311d68..cbfeba20397 100644
--- a/src/doc/en/reference/conf_sub.py
+++ b/src/doc/en/reference/conf_sub.py
@@ -42,6 +42,11 @@
     title = name.capitalize()
 title = title.replace('`', '$')
 
+# We use the directory's name to add a small edit button.
+html_theme_options.update({
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/reference/{name}/index.rst'),
+})
+
 # General information about the project.
 project = title
 
diff --git a/src/doc/en/thematic_tutorials/conf.py b/src/doc/en/thematic_tutorials/conf.py
index 73910657b2b..fc8dbc2a2cb 100644
--- a/src/doc/en/thematic_tutorials/conf.py
+++ b/src/doc/en/thematic_tutorials/conf.py
@@ -24,7 +24,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/en/thematic_tutorials",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/thematic_tutorials', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/en/tutorial/conf.py b/src/doc/en/tutorial/conf.py
index 957b215193d..b7e596ee913 100644
--- a/src/doc/en/tutorial/conf.py
+++ b/src/doc/en/tutorial/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/en/tutorial",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/en/tutorial', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/es/a_tour_of_sage/conf.py b/src/doc/es/a_tour_of_sage/conf.py
index dd690c41184..974418c7ec8 100644
--- a/src/doc/es/a_tour_of_sage/conf.py
+++ b/src/doc/es/a_tour_of_sage/conf.py
@@ -24,7 +24,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/es/a_tour_of_sage",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/es/a_tour_of_sage', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/es/tutorial/conf.py b/src/doc/es/tutorial/conf.py
index 8d82ca43b43..f82f9631e8d 100644
--- a/src/doc/es/tutorial/conf.py
+++ b/src/doc/es/tutorial/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/es/tutorial",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/es/tutorial', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/fr/a_tour_of_sage/conf.py b/src/doc/fr/a_tour_of_sage/conf.py
index 7a9ea830793..db98a3cce69 100644
--- a/src/doc/fr/a_tour_of_sage/conf.py
+++ b/src/doc/fr/a_tour_of_sage/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/fr/a_tour_of_sage",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/fr/a_tour_of_sage', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/fr/tutorial/conf.py b/src/doc/fr/tutorial/conf.py
index 9fc1e6d6ee6..41e190c8780 100644
--- a/src/doc/fr/tutorial/conf.py
+++ b/src/doc/fr/tutorial/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/fr/tutorial",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/fr/tutorial', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/hu/a_tour_of_sage/conf.py b/src/doc/hu/a_tour_of_sage/conf.py
index 422420e4681..7000cbb6323 100644
--- a/src/doc/hu/a_tour_of_sage/conf.py
+++ b/src/doc/hu/a_tour_of_sage/conf.py
@@ -24,7 +24,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/hu/a_tour_of_sage",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/hu/a_tour_of_sage', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/it/a_tour_of_sage/conf.py b/src/doc/it/a_tour_of_sage/conf.py
index ed49ebed736..2fb3a25c144 100644
--- a/src/doc/it/a_tour_of_sage/conf.py
+++ b/src/doc/it/a_tour_of_sage/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/it/a_tour_of_sage",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/it/a_tour_of_sage', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/it/faq/conf.py b/src/doc/it/faq/conf.py
index de033f0714d..c6c5827f9d9 100644
--- a/src/doc/it/faq/conf.py
+++ b/src/doc/it/faq/conf.py
@@ -24,7 +24,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/it/faq",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/it/faq', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/it/tutorial/conf.py b/src/doc/it/tutorial/conf.py
index c614e2011a9..8b94a0b51d6 100644
--- a/src/doc/it/tutorial/conf.py
+++ b/src/doc/it/tutorial/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/it/tutorial",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/it/tutorial', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/ja/a_tour_of_sage/conf.py b/src/doc/ja/a_tour_of_sage/conf.py
index 8aea104cd8b..da418f5b2a2 100644
--- a/src/doc/ja/a_tour_of_sage/conf.py
+++ b/src/doc/ja/a_tour_of_sage/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/ja/a_tour_of_sage",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/ja/a_tour_of_sage', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/ja/tutorial/conf.py b/src/doc/ja/tutorial/conf.py
index bbcbab2ff51..22418475be8 100644
--- a/src/doc/ja/tutorial/conf.py
+++ b/src/doc/ja/tutorial/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/ja/tutorial",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/ja/tutorial', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/pt/a_tour_of_sage/conf.py b/src/doc/pt/a_tour_of_sage/conf.py
index e5e65ce56ae..80ed6430bb4 100644
--- a/src/doc/pt/a_tour_of_sage/conf.py
+++ b/src/doc/pt/a_tour_of_sage/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/pt/a_tour_of_sage",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/pt/a_tour_of_sage', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/pt/tutorial/conf.py b/src/doc/pt/tutorial/conf.py
index 7a2e1a0434e..bf96e55eb51 100644
--- a/src/doc/pt/tutorial/conf.py
+++ b/src/doc/pt/tutorial/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/pt/tutorial",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/pt/tutorial', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/ru/tutorial/conf.py b/src/doc/ru/tutorial/conf.py
index 0055c7daa87..7df7bf4b6ae 100644
--- a/src/doc/ru/tutorial/conf.py
+++ b/src/doc/ru/tutorial/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/ru/tutorial",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/ru/tutorial', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/doc/tr/a_tour_of_sage/conf.py b/src/doc/tr/a_tour_of_sage/conf.py
index 6b75c1f136f..afacc779fe9 100644
--- a/src/doc/tr/a_tour_of_sage/conf.py
+++ b/src/doc/tr/a_tour_of_sage/conf.py
@@ -22,7 +22,7 @@
 
 # Add a small edit button.
 html_theme_options.update({
-  "source_directory": "src/doc/tr/a_tour_of_sage",
+  'source_edit_link': os.path.join(source_repository, f'blob/{version}/src/doc/tr/a_tour_of_sage', '{filename}'),
 })
 
 # General information about the project.
diff --git a/src/sage/misc/sageinspect.py b/src/sage/misc/sageinspect.py
index aff47ef96bb..dbd3a29aa42 100644
--- a/src/sage/misc/sageinspect.py
+++ b/src/sage/misc/sageinspect.py
@@ -3,14 +3,6 @@
 
 This module extends parts of Python's inspect module to Cython objects.
 
-AUTHORS:
-
-- originally taken from Fernando Perez's IPython
-- William Stein (extensive modifications)
-- Nick Alexander (extensions)
-- Nick Alexander (testing)
-- Simon King (some extension for Cython, generalisation of SageArgSpecVisitor)
-
 EXAMPLES::
 
     sage: from sage.misc.sageinspect import *
@@ -112,6 +104,22 @@ def foo(unsigned int x=1, a=')"', b={not (2+1==3):'bar'}, *args, **kwds): return
     sage: sage_getargspec(foo)
     FullArgSpec(args=['x', 'a', 'b'], varargs='args', varkw='kwds', defaults=(1, ')"', {False: 'bar'}), kwonlyargs=[], kwonlydefaults=None, annotations={})
 
+AUTHORS:
+
+- Originally taken from Fernando Perez's IPython
+- William Stein: extensive modifications
+- William Stein: ``_sage_getargspec_cython()``: a modified version of
+  ``inspect.getargspec`` from the Python Standard Library, which was taken from
+  IPython for use in Sage.
+- Nick Alexander: extensions, testing
+- Simon King: some extension for Cython, generalisation of SageArgSpecVisitor
+- Simon King: ``sage_getsourcelines()``: if a class has no docstring then let the
+  class definition be found starting from the ``__init__`` method.
+- Simon King: ``sage_getsourcelines()``: Get source lines for dynamic classes
+- Simon King (2013-02): ``_sage_getargspec_cython()``: recognise varargs and
+  default values in cython code, and return an ``ArgSpec``.
+- Simon King: ``_sage_getargspec_cython()``: Return an ``ArgSpec``, fix some bugs.
+- Simon King (2011-09): :func:`_sage_getsourcelines_name_with_dot`
 """
 
 import ast
@@ -282,11 +290,6 @@ def _extract_embedded_position(docstring):
         ....:     print(f.read())
         cpdef test_funct(x,y): return
 
-    AUTHORS:
-
-    - William Stein
-    - Extensions by Nick Alexander
-    - Extension for interactive Cython code by Simon King
     """
     try:
         res = __embedded_position_re.search(docstring)
@@ -334,10 +337,6 @@ def _extract_embedded_signature(docstring, name):
 
     INPUT: ``docstring`` (string)
 
-    AUTHORS:
-
-    - Simon King
-
     EXAMPLES::
 
         sage: from sage.misc.sageinspect import _extract_embedded_signature
@@ -712,10 +711,6 @@ def visit_BoolOp(self, node):
 
         - The result that ``node`` represents
 
-        AUTHOR:
-
-        - Simon King
-
         EXAMPLES::
 
             sage: import ast, sage.misc.sageinspect as sms
@@ -751,10 +746,6 @@ def visit_Compare(self, node):
 
         - The result that ``node`` represents
 
-        AUTHOR:
-
-        - Simon King
-
         EXAMPLES::
 
             sage: import ast, sage.misc.sageinspect as sms
@@ -803,10 +794,6 @@ def visit_BinOp(self, node):
 
         - The result that ``node`` represents
 
-        AUTHOR:
-
-        - Simon King
-
         EXAMPLES::
 
             sage: import ast, sage.misc.sageinspect as sms
@@ -873,10 +860,6 @@ def visit_UnaryOp(self, node):
 
         - The result that ``node`` represents
 
-        AUTHOR:
-
-        - Simon King
-
         EXAMPLES::
 
             sage: import ast, sage.misc.sageinspect as sms
@@ -1223,11 +1206,7 @@ def _sage_getargspec_cython(source):
                     kwonlyargs=[], kwonlydefaults=None, annotations={})
 
 
-    AUTHORS:
 
-    - Nick Alexander: original version
-    - Simon King (02-2013): recognise varargs and default values in
-      cython code, and return an ``ArgSpec``.
 
     """
     defpos = source.find('def ')
@@ -1394,10 +1373,6 @@ def sage_getfile(obj):
         sage: sage_getfile(range)
         ''
 
-    AUTHORS:
-
-    - Nick Alexander
-    - Simon King
     """
     # We try to extract from docstrings, but not using Python's inspect
     # because _sage_getdoc_unformatted is more robust.
@@ -1667,12 +1642,6 @@ def foo(x, a='\')"', b={not (2+1==3):'bar'}): return
         sage: shell.run_cell('f??')
         ...the source code string...
 
-    AUTHORS:
-
-    - William Stein: a modified version of inspect.getargspec from the
-      Python Standard Library, which was taken from IPython for use in Sage.
-    - Extensions by Nick Alexander
-    - Simon King: Return an ``ArgSpec``, fix some bugs.
     """
     from sage.misc.lazy_attribute import lazy_attribute
     from sage.misc.abstract_method import AbstractMethod
@@ -1913,11 +1882,6 @@ def sage_getdef(obj, obj_name=''):
 
     If an exception is generated, None is returned instead and the
     exception is suppressed.
-
-    AUTHORS:
-
-    - William Stein
-    - extensions by Nick Alexander
     """
     try:
         spec = sage_getargspec(obj)
@@ -1982,11 +1946,6 @@ def _sage_getdoc_unformatted(obj):
         Exception: no doc here
         sage: _sage_getdoc_unformatted(obj)
         ''
-
-    AUTHORS:
-
-    - William Stein
-    - extensions by Nick Alexander
     """
     if obj is None:
         return ''
@@ -2123,11 +2082,6 @@ def sage_getdoc(obj, obj_name='', embedded=False):
         'original documentation\n'
         sage: sage_getdoc(f1)
         'specialised documentation\n'
-
-    AUTHORS:
-
-    - William Stein
-    - extensions by Nick Alexander
     """
     import sage.misc.sagedoc
     if obj is None:
@@ -2168,11 +2122,6 @@ def sage_getsource(obj):
         'identity_matrix(ring, n=0, sparse=False):'
         sage: sage_getsource(identity_matrix)[19:60]                                    # needs sage.modules
         'identity_matrix(ring, n=0, sparse=False):'
-
-    AUTHORS:
-
-    - William Stein
-    - extensions by Nick Alexander
     """
     # First we should check if the object has a _sage_src_
     # method.  If it does, we just return the output from
@@ -2234,10 +2183,6 @@ class ParentMethods:
     has a docstring. Otherwise, the code of ``B`` could not be found (Cython
     inserts embedding information into the docstring) and thus the code of
     ``B.A`` couldn't be found either.
-
-    AUTHOR:
-
-    - Simon King (2011-09)
     """
     # First, split the name:
     if '.' in obj.__name__:
@@ -2344,26 +2289,29 @@ def sage_getsourcelines(obj):
 
     EXAMPLES::
 
+        sage: # needs sage.modules
         sage: from sage.misc.sageinspect import sage_getsourcelines
-        sage: sage_getsourcelines(matrix)[1]                                            # needs sage.modules
+        sage: sage_getsourcelines(matrix)[1]
         21
-        sage: sage_getsourcelines(matrix)[0][0]                                         # needs sage.modules
+        sage: sage_getsourcelines(matrix)[0][0]
         'def matrix(*args, **kwds):\n'
 
     Some classes customize this using a ``_sage_src_lines_`` method,
     which gives the source lines of a class instance, but not the class
     itself. We demonstrate this for :class:`CachedFunction`::
 
-        sage: cachedfib = cached_function(fibonacci)                                    # needs sage.combinat
-        sage: sage_getsourcelines(cachedfib)[0][0]                                      # needs sage.combinat
+        sage: # needs sage.combinat
+        sage: cachedfib = cached_function(fibonacci)
+        sage: sage_getsourcelines(cachedfib)[0][0]
         'def fibonacci(n, algorithm="pari") -> Integer:\n'
-        sage: sage_getsourcelines(type(cachedfib))[0][0]                                # needs sage.combinat
+        sage: sage_getsourcelines(type(cachedfib))[0][0]
         'cdef class CachedFunction():\n'
 
     TESTS::
 
-        sage: cython('''cpdef test_funct(x,y): return''')                               # needs sage.misc.cython
-        sage: sage_getsourcelines(test_funct)                                           # needs sage.misc.cython
+        sage: # needs sage.misc.cython
+        sage: cython('''cpdef test_funct(x,y): return''')
+        sage: sage_getsourcelines(test_funct)
         (['cpdef test_funct(x,y): return\n'], 1)
 
     The following tests that an instance of ``functools.partial`` is correctly
@@ -2440,15 +2388,6 @@ class Element():
           '                       Ideal_generic):\n',
           '    def __init__(self, ring, gens, coerce=True):\n',
           ...)
-
-    AUTHORS:
-
-    - William Stein
-    - Extensions by Nick Alexander
-    - Extension to interactive Cython code by Simon King
-    - Simon King: If a class has no docstring then let the class
-      definition be found starting from the ``__init__`` method.
-    - Simon King: Get source lines for dynamic classes.
     """
     # First try the method _sage_src_lines_(), which is meant to give
     # the source lines of an object (not of its type!).
@@ -2488,11 +2427,7 @@ class Element():
     pos = _extract_embedded_position(d)
     if pos is None:
         try:
-            # BEWARE HERE
-            # inspect gives str (=bytes) in python2
-            # and str (=unicode) in python3
             return inspect.getsourcelines(obj)
-
         except (OSError, TypeError) as err:
             try:
                 objinit = obj.__init__
diff --git a/src/sage_docbuild/conf.py b/src/sage_docbuild/conf.py
index ccab5290b9a..b1b95eb40d5 100644
--- a/src/sage_docbuild/conf.py
+++ b/src/sage_docbuild/conf.py
@@ -21,14 +21,12 @@
 import importlib
 import sys
 import os
+import dateutil.parser
 import sphinx
 import sphinx.ext.intersphinx as intersphinx
-import dateutil.parser
-
 from sphinx import highlighting
 from sphinx.transforms import SphinxTransform
 from IPython.lib.lexers import IPythonConsoleLexer, IPyLexer
-
 from sage.misc.sagedoc import extlinks
 from sage.env import SAGE_DOC_SRC, SAGE_DOC, PPLPY_DOCS, MATHJAX_DIR
 from sage.misc.latex_macros import sage_mathjax_macros
@@ -49,6 +47,7 @@
     'sphinx.ext.todo',
     'sphinx.ext.extlinks',
     'sphinx.ext.mathjax',
+    'sphinx.ext.linkcode',
     'sphinx_copybutton',
     'sphinx_inline_tabs',
     'IPython.sphinxext.ipython_directive',
@@ -196,6 +195,9 @@ def sphinx_plot(graphics, **kwds):
 version = sage.version.version
 release = sage.version.version
 
+source_repository = 'https://github.com/sagemath/sage/'
+source_branch = 'develop'
+
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
 # language = None
@@ -253,6 +255,7 @@ def sphinx_plot(graphics, **kwds):
 # displaying all parents.
 toc_object_entries_show_parents = 'hide'
 
+# -----------------------
 # Extension configuration
 # -----------------------
 
@@ -311,6 +314,38 @@ def set_intersphinx_mappings(app, config):
 copybutton_exclude = '.linenos, .c1'  # exclude single comments (in particular, # optional!)
 copybutton_only_copy_prompt_lines = True
 
+
+# https://www.sphinx-doc.org/en/master/usage/extensions/linkcode.html
+def linkcode_resolve(domain, info):
+    import inspect
+    from urllib.parse import quote
+    from sage.misc.sageinspect import sage_getsourcelines
+    if domain != 'py':
+        return None
+    if info['module']:
+        m = importlib.import_module(info['module'])
+        filename = quote(info['module'].replace('.', '/'))
+        if m.__file__.endswith('py'):
+            filename += '.py'
+        else:
+            filename += '.pyx'
+        if 'fullname' in info:
+            fullname = info['fullname']
+            obj = m
+            try:
+                for attr in fullname.split('.'):
+                    obj = getattr(obj, attr)
+                lineno = sage_getsourcelines(obj)[-1]
+            except:
+                return None
+            anchor = f'#L{lineno}'
+        else:
+            anchor = ''
+        return f"{source_repository}blob/{version}/src/{filename}{anchor}"
+    return None
+
+
+# -----------------------
 # Options for HTML output
 # -----------------------
 
@@ -341,15 +376,15 @@ def set_intersphinx_mappings(app, config):
     # Furo can add a small edit button to each document to allow visitors to
     # easily propose changes to that document using the repository’s source
     # control system.
-    "source_repository": "https://github.com/sagemath/sage/",
-    "source_branch": "develop",
+    "source_repository": source_repository,
+    "source_branch": source_branch,
 }
 
-if not version.split('.')[-1].isnumeric():
+if not version.split('.')[-1].isnumeric():  # develop version
     html_theme_options.update({
-        "announcement": f'This is documentation for <em>Sage development version {version}</em>. '
-                         'The documentation of the latest stable version is available '
-                         '<a href="https://doc.sagemath.org/html/en/index.html">here</a>.',
+        "announcement": f'This is documentation for Sage development version {version}. '
+                         'The documentation for the latest stable version is available '
+                         '<a href="https://doc.sagemath.org/html/en/index.html">here</a>.'
 })
 
 # The name of the Pygments (syntax highlighting) style to use. This
@@ -445,7 +480,7 @@ def set_intersphinx_mappings(app, config):
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
-#html_last_updated_fmt = '%b %d, %Y'
+# html_last_updated_fmt = '%b %d, %Y'
 
 # If true, SmartyPants will be used to convert quotes and dashes to
 # typographically correct entities.
@@ -467,27 +502,29 @@ def set_intersphinx_mappings(app, config):
 modindex_common_prefix = ['sage.']
 
 # If false, no index is generated.
-#html_use_index = True
+# html_use_index = True
 
 # If true, the index is split into individual pages for each letter.
 html_split_index = True
 
 # If true, the reST sources are included in the HTML build as _sources/<name>.
-#html_copy_source = True
+# html_copy_source = True
 
 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the
 # base URL from which the finished HTML is served.
-#html_use_opensearch = ''
+# html_use_opensearch = ''
 
 # If nonempty, this is the file name suffix for HTML files (e.g. ".xhtml").
-#html_file_suffix = ''
+# html_file_suffix = ''
 
 # Output file base name for HTML help builder.
-#htmlhelp_basename = ''
+# htmlhelp_basename = ''
 
+# ------------------------
 # Options for LaTeX output
 # ------------------------
+
 # See http://sphinx-doc.org/config.html#confval-latex_elements
 latex_elements = {}
 
@@ -530,13 +567,14 @@ def set_intersphinx_mappings(app, config):
 """
 
 # Documents to append as an appendix to all manuals.
-#latex_appendices = []
+# latex_appendices = []
 
 # If false, no module index is generated.
-#latex_use_modindex = True
+# latex_use_modindex = True
 
-#####################################################
+# -------------------------
 # add LaTeX macros for Sage
+# -------------------------
 
 from sage.misc.latex_macros import sage_latex_macros
 
@@ -551,8 +589,9 @@ def set_intersphinx_mappings(app, config):
     # used when building html version
     pngmath_latex_preamble += macro + '\n'
 
-#####################################################
+# ------------------------------------------
 # add custom context variables for templates
+# ------------------------------------------
 
 def add_page_context(app, pagename, templatename, context, doctree):
     # # The template function
@@ -738,7 +777,6 @@ def nitpick_patch_config(app):
     '__builtin__',
 ]
 
-
 def check_nested_class_picklability(app, what, name, obj, skip, options):
     """
     Print a warning if pickling is broken for nested classes.