diff --git a/base/docs/Docs.jl b/base/docs/Docs.jl
index e5974d3280308..95724dc97bb73 100644
--- a/base/docs/Docs.jl
+++ b/base/docs/Docs.jl
@@ -650,11 +650,37 @@ function loaddocs(docs::Vector{Core.SimpleVector})
     nothing
 end
 
+# FIXME: formatdoc, parsedoc, apropos, and doc are defined here (but only doc is exported)
+# for historical reasons (#25738), but are *implemented* in REPL/src/docview.jl, while
+# apropos is *exported* by InteractiveUtils and doc is exported by Docs.  Seems
+# like a more sensible refactoring should be possible.
+
 function formatdoc end
 function parsedoc end
+
+"""
+    apropos([io::IO=stdout], pattern::Union{AbstractString,Regex})
+
+Search available docstrings for entries containing `pattern`.
+
+When `pattern` is a string, case is ignored. Results are printed to `io`.
+
+`apropos` can be called from the help mode in the REPL by wrapping the query in double quotes:
+```
+help?> "pattern"
+```
+"""
 function apropos end
-function doc end
 
+"""
+    Docs.doc(binding, sig)
+
+Return all documentation that matches both `binding` and `sig`.
+
+If `getdoc` returns a non-`nothing` result on the value of the binding, then a
+dynamic docstring is returned instead of one based on the binding itself.
+"""
+function doc end
 
 """
     Docs.hasdoc(mod::Module, sym::Symbol)::Bool
diff --git a/base/libc.jl b/base/libc.jl
index 1fcf763e4e124..359ca6a7f8c31 100644
--- a/base/libc.jl
+++ b/base/libc.jl
@@ -45,6 +45,11 @@ show(io::IO, fd::RawFD) = print(io, "RawFD(", bitcast(UInt32, fd), ')')  # avoid
 
 # Wrapper for an OS file descriptor (for Windows)
 if Sys.iswindows()
+    @doc """
+        WindowsRawSocket
+
+    Primitive type which wraps the native Windows file `HANDLE`.
+    """
     primitive type WindowsRawSocket sizeof(Ptr) * 8 end # On Windows file descriptors are HANDLE's and 64-bit on 64-bit Windows
     WindowsRawSocket(handle::Ptr{Cvoid}) = bitcast(WindowsRawSocket, handle)
     WindowsRawSocket(handle::WindowsRawSocket) = handle
diff --git a/stdlib/Artifacts/test/runtests.jl b/stdlib/Artifacts/test/runtests.jl
index db0d5d4c53ab1..2255930baf8e4 100644
--- a/stdlib/Artifacts/test/runtests.jl
+++ b/stdlib/Artifacts/test/runtests.jl
@@ -261,3 +261,9 @@ end
     @test length(Base.manifest_names) == 2n # there are two manifest names per project name
     @test length(Base.preferences_names) == n
 end
+
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(Artifacts)
+    @test_broken isempty(undoc)
+    @test undoc == [:Artifacts]
+end
diff --git a/stdlib/Base64/test/runtests.jl b/stdlib/Base64/test/runtests.jl
index 11d0a3cca4348..145576f6ea3f4 100644
--- a/stdlib/Base64/test/runtests.jl
+++ b/stdlib/Base64/test/runtests.jl
@@ -1,7 +1,8 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
 using Test, Random
-import Base64:
+using Base64:
+    Base64,
     Base64EncodePipe,
     base64encode,
     Base64DecodePipe,
@@ -142,3 +143,7 @@ end
         @test String(base64decode(splace(longEncodedText))) == longDecodedText
     end
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Base64))
+end
diff --git a/stdlib/CRC32c/test/runtests.jl b/stdlib/CRC32c/test/runtests.jl
index 41a7ea2ab62fa..e1bd75d0e15f6 100644
--- a/stdlib/CRC32c/test/runtests.jl
+++ b/stdlib/CRC32c/test/runtests.jl
@@ -77,3 +77,7 @@ end
 crc32c_sw(io::IO, crc::UInt32=0x00000000) = crc32c_sw(io, typemax(Int64), crc)
 test_crc32c(crc32c)
 test_crc32c(crc32c_sw)
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(CRC32c))
+end
diff --git a/stdlib/Dates/test/runtests.jl b/stdlib/Dates/test/runtests.jl
index de063135427a9..7ac46bd69139c 100644
--- a/stdlib/Dates/test/runtests.jl
+++ b/stdlib/Dates/test/runtests.jl
@@ -2,8 +2,16 @@
 
 module DateTests
 
+using Test, Dates
+
 for file in readlines(joinpath(@__DIR__, "testgroups"))
     include(file * ".jl")
 end
 
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(Dates)
+    @test_broken isempty(undoc)
+    @test undoc == [:adjust]
+end
+
 end
diff --git a/stdlib/FileWatching/test/runtests.jl b/stdlib/FileWatching/test/runtests.jl
index 75b17b5f0e511..a02ed3931a349 100644
--- a/stdlib/FileWatching/test/runtests.jl
+++ b/stdlib/FileWatching/test/runtests.jl
@@ -447,4 +447,10 @@ rm(dir)
     include("pidfile.jl")
 end
 
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(FileWatching)
+    @test_broken isempty(undoc)
+    @test undoc == [:FDWatcher, :FileMonitor, :FolderMonitor, :PollingFileWatcher]
+end
+
 end # testset
diff --git a/stdlib/Future/test/runtests.jl b/stdlib/Future/test/runtests.jl
index 6deffe74d891c..6e02f17358ab3 100644
--- a/stdlib/Future/test/runtests.jl
+++ b/stdlib/Future/test/runtests.jl
@@ -2,3 +2,7 @@
 
 using Test
 using Future
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Future))
+end
diff --git a/stdlib/InteractiveUtils/test/runtests.jl b/stdlib/InteractiveUtils/test/runtests.jl
index 1309e11280bfa..b7db40168d8a6 100644
--- a/stdlib/InteractiveUtils/test/runtests.jl
+++ b/stdlib/InteractiveUtils/test/runtests.jl
@@ -721,3 +721,9 @@ end
 end
 
 @test Base.infer_effects(sin, (Int,)) == InteractiveUtils.@infer_effects sin(42)
+
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(InteractiveUtils)
+    @test_broken isempty(undoc)
+    @test undoc == [:InteractiveUtils]
+end
diff --git a/stdlib/LibGit2/test/runtests.jl b/stdlib/LibGit2/test/runtests.jl
index 88aea77f25671..4d2f4f9104c4e 100644
--- a/stdlib/LibGit2/test/runtests.jl
+++ b/stdlib/LibGit2/test/runtests.jl
@@ -1,6 +1,11 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
-using Test
+using Test, LibGit2
+
 @testset verbose=true "LibGit2 $test" for test in eachline(joinpath(@__DIR__, "testgroups"))
     include("$test.jl")
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(LibGit2))
+end
diff --git a/stdlib/Libdl/test/runtests.jl b/stdlib/Libdl/test/runtests.jl
index e500b68dec34b..cbff36c870fe7 100644
--- a/stdlib/Libdl/test/runtests.jl
+++ b/stdlib/Libdl/test/runtests.jl
@@ -329,3 +329,9 @@ end
     lazy_name_lazy_lib = LazyLibrary(libname)
     @test dlpath(lazy_name_lazy_lib) == realpath(string(libname))
 end; end
+
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(Libdl)
+    @test_broken isempty(undoc)
+    @test undoc == [:Libdl]
+end
diff --git a/stdlib/LinearAlgebra/test/runtests.jl b/stdlib/LinearAlgebra/test/runtests.jl
index 29581313c18d5..55bc119756ce8 100644
--- a/stdlib/LinearAlgebra/test/runtests.jl
+++ b/stdlib/LinearAlgebra/test/runtests.jl
@@ -1,5 +1,12 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
+using Test, LinearAlgebra
 
 for file in readlines(joinpath(@__DIR__, "testgroups"))
     include(file * ".jl")
 end
+
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(LinearAlgebra)
+    @test_broken isempty(undoc)
+    @test undoc == [:ColumnNorm, :LAPACKException, :NoPivot, :RankDeficientException, :RowMaximum, :RowNonZero, :copy_transpose!]
+end
diff --git a/stdlib/Logging/test/runtests.jl b/stdlib/Logging/test/runtests.jl
index e7b3fbca2098d..e0fc6a0bc3770 100644
--- a/stdlib/Logging/test/runtests.jl
+++ b/stdlib/Logging/test/runtests.jl
@@ -300,4 +300,10 @@ end
     @test occursin("CustomLog2: hello", String(take!(buf)))
 end
 
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(Logging)
+    @test_broken isempty(undoc)
+    @test undoc == [:AboveMaxLevel, :BelowMinLevel]
+end
+
 end
diff --git a/stdlib/Markdown/test/runtests.jl b/stdlib/Markdown/test/runtests.jl
index 84f0868747567..116282a0bea3b 100644
--- a/stdlib/Markdown/test/runtests.jl
+++ b/stdlib/Markdown/test/runtests.jl
@@ -1293,3 +1293,7 @@ end
     # see issue #42139
     @test md"<一轮红日初升>" |> html == """<p>&lt;一轮红日初升&gt;</p>\n"""
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Markdown))
+end
diff --git a/stdlib/Mmap/test/runtests.jl b/stdlib/Mmap/test/runtests.jl
index 0b3cb0b9f1a42..ebd16a45ba0ed 100644
--- a/stdlib/Mmap/test/runtests.jl
+++ b/stdlib/Mmap/test/runtests.jl
@@ -339,3 +339,7 @@ open(file, "r+") do s
     finalize(A); A = nothing; GC.gc()
 end
 rm(file)
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Mmap))
+end
diff --git a/stdlib/Printf/test/runtests.jl b/stdlib/Printf/test/runtests.jl
index 71ec369af4ef7..a80affff37d11 100644
--- a/stdlib/Printf/test/runtests.jl
+++ b/stdlib/Printf/test/runtests.jl
@@ -1145,6 +1145,12 @@ end
     @test_throws Printf.InvalidFormatStringError Printf.Format("%z")
 end
 
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(Printf)
+    @test_broken isempty(undoc)
+    @test undoc == [:Printf]
+end
+
 # issue #52749
 @test @sprintf("%.160g", 1.38e-23) == "1.380000000000000060010582465734078799297660966782642624395399644741944111814291318296454846858978271484375e-23"
 
diff --git a/stdlib/Profile/test/runtests.jl b/stdlib/Profile/test/runtests.jl
index d7358dc20e853..169e70bfa7f36 100644
--- a/stdlib/Profile/test/runtests.jl
+++ b/stdlib/Profile/test/runtests.jl
@@ -300,3 +300,9 @@ end
 end
 
 include("allocs.jl")
+
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(Profile)
+    @test_broken isempty(undoc)
+    @test undoc == [:Allocs]
+end
diff --git a/stdlib/REPL/src/docview.jl b/stdlib/REPL/src/docview.jl
index 41f3020447090..1d5bd12cdda58 100644
--- a/stdlib/REPL/src/docview.jl
+++ b/stdlib/REPL/src/docview.jl
@@ -198,14 +198,6 @@ function insert_internal_warning(other, internal_access::Set{Pair{Module,Symbol}
     other
 end
 
-"""
-    Docs.doc(binding, sig)
-
-Return all documentation that matches both `binding` and `sig`.
-
-If `getdoc` returns a non-`nothing` result on the value of the binding, then a
-dynamic docstring is returned instead of one based on the binding itself.
-"""
 function doc(binding::Binding, sig::Type = Union{})
     if defined(binding)
         result = getdoc(resolve(binding), sig)
@@ -920,18 +912,6 @@ stripmd(x::Markdown.Footnote) = "$(stripmd(x.id)) $(stripmd(x.text))"
 stripmd(x::Markdown.Table) =
     join([join(map(stripmd, r), " ") for r in x.rows], " ")
 
-"""
-    apropos([io::IO=stdout], pattern::Union{AbstractString,Regex})
-
-Search available docstrings for entries containing `pattern`.
-
-When `pattern` is a string, case is ignored. Results are printed to `io`.
-
-`apropos` can be called from the help mode in the REPL by wrapping the query in double quotes:
-```
-help?> "pattern"
-```
-"""
 apropos(string) = apropos(stdout, string)
 apropos(io::IO, string) = apropos(io, Regex("\\Q$string", "i"))
 
diff --git a/stdlib/REPL/test/repl.jl b/stdlib/REPL/test/repl.jl
index 7896b589612e3..f16ac0e07689a 100644
--- a/stdlib/REPL/test/repl.jl
+++ b/stdlib/REPL/test/repl.jl
@@ -1749,3 +1749,9 @@ let io = IOBuffer()
     seek(io, 0)
     @test countlines(io) == 2
 end
+
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(REPL)
+    @test_broken isempty(undoc)
+    @test undoc == [:AbstractREPL, :BasicREPL, :LineEditREPL, :StreamREPL]
+end
diff --git a/stdlib/Random/test/runtests.jl b/stdlib/Random/test/runtests.jl
index 61cee5c952c51..16a2f89753f3b 100644
--- a/stdlib/Random/test/runtests.jl
+++ b/stdlib/Random/test/runtests.jl
@@ -1232,3 +1232,7 @@ end
     @test xs isa Vector{Pair{Bool, Char}}
     @test length(xs) == 3
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Random))
+end
diff --git a/stdlib/Serialization/test/runtests.jl b/stdlib/Serialization/test/runtests.jl
index 46749d4375538..a7d5023e1ec51 100644
--- a/stdlib/Serialization/test/runtests.jl
+++ b/stdlib/Serialization/test/runtests.jl
@@ -655,3 +655,9 @@ end
     @test l2 == l1
     @test l2.parts === ()
 end
+
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(Serialization)
+    @test_broken isempty(undoc)
+    @test undoc == [:AbstractSerializer, :Serializer]
+end
diff --git a/stdlib/SharedArrays/test/runtests.jl b/stdlib/SharedArrays/test/runtests.jl
index 7f1bbb6891ce0..84dffafb3d92a 100644
--- a/stdlib/SharedArrays/test/runtests.jl
+++ b/stdlib/SharedArrays/test/runtests.jl
@@ -324,3 +324,7 @@ end
 @test SharedMatrix([0.1 0.2; 0.3 0.4]) == [0.1 0.2; 0.3 0.4]
 @test_throws MethodError SharedVector(rand(4,4))
 @test_throws MethodError SharedMatrix(rand(4))
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(SharedArrays))
+end
diff --git a/stdlib/Sockets/test/runtests.jl b/stdlib/Sockets/test/runtests.jl
index 02a994460afbf..2a812388d8373 100644
--- a/stdlib/Sockets/test/runtests.jl
+++ b/stdlib/Sockets/test/runtests.jl
@@ -682,3 +682,7 @@ end
 
 
 close(sockets_watchdog_timer)
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Sockets))
+end
diff --git a/stdlib/TOML/test/runtests.jl b/stdlib/TOML/test/runtests.jl
index 7376fab914636..e471068f36e7f 100644
--- a/stdlib/TOML/test/runtests.jl
+++ b/stdlib/TOML/test/runtests.jl
@@ -25,3 +25,9 @@ include("print.jl")
 include("parse.jl")
 
 @inferred TOML.parse("foo = 3")
+
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(TOML)
+    @test_broken isempty(undoc)
+    @test undoc == [:TOML]
+end
diff --git a/stdlib/Test/test/runtests.jl b/stdlib/Test/test/runtests.jl
index 1f93db2b5ed72..4f1077835c632 100644
--- a/stdlib/Test/test/runtests.jl
+++ b/stdlib/Test/test/runtests.jl
@@ -1582,3 +1582,7 @@ let
         end
     end
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Test))
+end
diff --git a/stdlib/UUIDs/test/runtests.jl b/stdlib/UUIDs/test/runtests.jl
index 1770b24b3abae..d2b9ee17f2e38 100644
--- a/stdlib/UUIDs/test/runtests.jl
+++ b/stdlib/UUIDs/test/runtests.jl
@@ -73,3 +73,7 @@ str = "22b4a8a1-e548-4eeb-9270-60426d66a48e"
 for r in rand(UInt128, 10^3)
     @test UUID(r) == UUID(string(UUID(r)))
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(UUIDs))
+end
diff --git a/stdlib/Unicode/test/runtests.jl b/stdlib/Unicode/test/runtests.jl
index 2ee7b88ae966b..7fa57508cffbf 100644
--- a/stdlib/Unicode/test/runtests.jl
+++ b/stdlib/Unicode/test/runtests.jl
@@ -534,3 +534,7 @@ isequal_normalized_naive(s1, s2; kws...) = normalize(s1; kws...) == normalize(s2
         @test !isequal_normalized("x\u0334\u0335", "x\u0335\u0334")
     end
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Unicode))
+end
diff --git a/test/broadcast.jl b/test/broadcast.jl
index 1e5752921bc93..2ae3d96b2a709 100644
--- a/test/broadcast.jl
+++ b/test/broadcast.jl
@@ -1176,6 +1176,12 @@ import Base.Broadcast: BroadcastStyle, DefaultArrayStyle
 f51129(v, x) = (1 .- (v ./ x) .^ 2)
 @test @inferred(f51129([13.0], 6.5)) == [-3.0]
 
+@testset "Docstrings" begin
+    undoc = Docs.undocumented_names(Broadcast)
+    @test_broken isempty(undoc)
+    @test undoc == [:dotview]
+end
+
 @testset "broadcast for `AbstractArray` without `CartesianIndex` support" begin
     struct BVec52775 <: AbstractVector{Int}
         a::Vector{Int}
diff --git a/test/checked.jl b/test/checked.jl
index bacda3db75dec..bbc53ddb55ed2 100644
--- a/test/checked.jl
+++ b/test/checked.jl
@@ -358,3 +358,7 @@ end
     @test checked_mul(1, 2, 3, 4, 5, 6, 7) === 5040
     @test checked_mul(1, 2, 3, 4, 5, 6, 7, 8) === 40320
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(Base.Checked))
+end
diff --git a/test/docs.jl b/test/docs.jl
index 190bcaee6adf5..4eab0dd36361d 100644
--- a/test/docs.jl
+++ b/test/docs.jl
@@ -1556,3 +1556,9 @@ Base.@ccallable c51586_long()::Int = 3
 
 @test docstrings_equal(@doc(c51586_short()), doc"ensure we can document ccallable functions")
 @test docstrings_equal(@doc(c51586_long()), doc"ensure we can document ccallable functions")
+
+@testset "Docs docstrings" begin
+    undoc = Docs.undocumented_names(Docs)
+    @test_broken isempty(undoc)
+    @test undoc == [Symbol("@var")]
+end
diff --git a/test/filesystem.jl b/test/filesystem.jl
index 79beea9f66ac1..c9bab69c586b3 100644
--- a/test/filesystem.jl
+++ b/test/filesystem.jl
@@ -40,3 +40,9 @@ import Base.Filesystem: S_IRUSR, S_IRGRP, S_IROTH
   @test S_IRUSR & ~S_IRGRP == S_IRUSR
   @test typeof(S_IRUSR) == typeof(S_IRGRP) == typeof(S_IROTH)
 end
+
+@testset "Base.Filesystem docstrings" begin
+  undoc = Docs.undocumented_names(Base.Filesystem)
+  @test_broken isempty(undoc)
+  @test undoc == [:File, :Filesystem, :JL_O_APPEND, :JL_O_ASYNC, :JL_O_CLOEXEC, :JL_O_CREAT, :JL_O_DIRECT, :JL_O_DIRECTORY, :JL_O_DSYNC, :JL_O_EXCL, :JL_O_FSYNC, :JL_O_LARGEFILE, :JL_O_NDELAY, :JL_O_NOATIME, :JL_O_NOCTTY, :JL_O_NOFOLLOW, :JL_O_NONBLOCK, :JL_O_PATH, :JL_O_RANDOM, :JL_O_RDONLY, :JL_O_RDWR, :JL_O_RSYNC, :JL_O_SEQUENTIAL, :JL_O_SHORT_LIVED, :JL_O_SYNC, :JL_O_TEMPORARY, :JL_O_TMPFILE, :JL_O_TRUNC, :JL_O_WRONLY, :S_IRGRP, :S_IROTH, :S_IRUSR, :S_IRWXG, :S_IRWXO, :S_IRWXU, :S_IWGRP, :S_IWOTH, :S_IWUSR, :S_IXGRP, :S_IXOTH, :S_IXUSR, :cptree, :futime, :rename, :sendfile, :unlink]
+end
diff --git a/test/gc.jl b/test/gc.jl
index 99b96a5ae1fd2..d5990582cc00a 100644
--- a/test/gc.jl
+++ b/test/gc.jl
@@ -33,3 +33,7 @@ end
     run_gctest("gc/chunks.jl")
     run_nonzero_page_utilization_test()
 end
+
+@testset "Base.GC docstrings" begin
+    @test isempty(Docs.undocumented_names(GC))
+end
diff --git a/test/iterators.jl b/test/iterators.jl
index 46e7c8b454335..74d7d61f0a496 100644
--- a/test/iterators.jl
+++ b/test/iterators.jl
@@ -1009,3 +1009,7 @@ end
 @testset "collect partition substring" begin
     @test collect(Iterators.partition(lstrip("01111", '0'), 2)) == ["11", "11"]
 end
+
+@testset "Iterators docstrings" begin
+    @test isempty(Docs.undocumented_names(Iterators))
+end
diff --git a/test/math.jl b/test/math.jl
index 248f99cebd987..f3c6dc5bb103f 100644
--- a/test/math.jl
+++ b/test/math.jl
@@ -1599,3 +1599,7 @@ end === Float64
     @test tanpi(big(1//1)) == big(0.0)
     @test cospi(big(1//1)) == big(-1.0)
 end
+
+@testset "Docstrings" begin
+    @test isempty(Docs.undocumented_names(MathConstants))
+end
diff --git a/test/meta.jl b/test/meta.jl
index be0ecf0cdb827..5fb1ebc0d3647 100644
--- a/test/meta.jl
+++ b/test/meta.jl
@@ -277,3 +277,7 @@ ci = code_lowered(g, Tuple{Val{true}})[1]
                                  [], 0, 0, :propagate)[1] == Expr(:isdefined, GlobalRef(Base, :foo))
 
 end
+
+@testset "Base.Meta docstrings" begin
+    @test isempty(Docs.undocumented_names(Meta))
+end
diff --git a/test/misc.jl b/test/misc.jl
index caa4a5fb599bf..03cf59acb59a3 100644
--- a/test/misc.jl
+++ b/test/misc.jl
@@ -1407,3 +1407,13 @@ end
     GC.gc(true); yield()
     @test in_fin[]
 end
+
+@testset "Base docstrings" begin
+    undoc = Docs.undocumented_names(Base)
+    @test_broken isempty(undoc)
+    @test undoc == [:BufferStream, :CanonicalIndexError, :CapturedException, :Filesystem, :IOServer, :InvalidStateException, :Order, :PipeEndpoint, :Sort, :TTY]
+end
+
+@testset "Base.Libc docstrings" begin
+    @test isempty(Docs.undocumented_names(Libc))
+end
diff --git a/test/ordering.jl b/test/ordering.jl
index 972d48c17b1af..3b5385b99be68 100644
--- a/test/ordering.jl
+++ b/test/ordering.jl
@@ -51,3 +51,9 @@ struct SomeOtherOrder <: Base.Order.Ordering end
 @test ord(<, abs, false, Forward) === By(abs, Lt(<))
 @test ord(<, abs, true, Forward) === ReverseOrdering(By(abs, Lt(<)))
 @test ord(<, abs, true, Reverse) === By(abs, Lt(<))
+
+@testset "Base.Order docstrings" begin
+    undoc = Docs.undocumented_names(Base.Order)
+    @test_broken isempty(undoc)
+    @test undoc == [:DirectOrdering, :ForwardOrdering, :Order, :ordtype]
+end
diff --git a/test/sorting.jl b/test/sorting.jl
index ad821e38efe55..d1875c9727a29 100644
--- a/test/sorting.jl
+++ b/test/sorting.jl
@@ -9,6 +9,12 @@ using Test
 isdefined(Main, :OffsetArrays) || @eval Main include("testhelpers/OffsetArrays.jl")
 using .Main.OffsetArrays
 
+@testset "Base.Sort docstrings" begin
+    undoc = Docs.undocumented_names(Base.Sort)
+    @test_broken isempty(undoc)
+    @test undoc == [:Algorithm, :SMALL_ALGORITHM, :SMALL_THRESHOLD, :Sort]
+end
+
 @testset "Order" begin
     @test Forward == ForwardOrdering()
     @test ReverseOrdering(Forward) == ReverseOrdering() == Reverse
diff --git a/test/stacktraces.jl b/test/stacktraces.jl
index be035e31833d3..caea8158315ff 100644
--- a/test/stacktraces.jl
+++ b/test/stacktraces.jl
@@ -268,3 +268,7 @@ struct F49231{a,b,c,d,e,f,g} end
     str = sprint(Base.show_backtrace, st, context = (:limit=>true, :stacktrace_types_limited => Ref(false), :color=>true, :displaysize=>(50,132)))
     @test contains(str, "[2] \e[0m\e[1m(::$F49231{Vector, Val{…}, Vector{…}, NTuple{…}, $Int, $Int, $Int})\e[22m\e[0m\e[1m(\e[22m\e[90ma\e[39m::\e[0m$Int, \e[90mb\e[39m::\e[0m$Int, \e[90mc\e[39m::\e[0m$Int\e[0m\e[1m)\e[22m\n\e[90m")
 end
+
+@testset "Base.StackTraces docstrings" begin
+    @test isempty(Docs.undocumented_names(StackTraces))
+end
diff --git a/test/sysinfo.jl b/test/sysinfo.jl
index 8864e3a48efc7..4bdc9aeba48f2 100644
--- a/test/sysinfo.jl
+++ b/test/sysinfo.jl
@@ -54,3 +54,9 @@ end
         @test !isempty(Sys.username())
     end
 end
+
+@testset "Base.Sys docstrings" begin
+    undoc = Docs.undocumented_names(Sys)
+    @test_broken isempty(undoc)
+    @test undoc == [:CPU_NAME, :JIT, :cpu_info, :cpu_summary]
+end
diff --git a/test/threads.jl b/test/threads.jl
index ad09304bbd80d..307742a4c292b 100644
--- a/test/threads.jl
+++ b/test/threads.jl
@@ -337,3 +337,7 @@ end
     # There must be at least two: one for the root test task and one for the async task:
     @test fetch(@async(@ccall(jl_get_num_stack_mappings()::Cint))) >= 2
 end
+
+@testset "Base.Threads docstrings" begin
+    @test isempty(Docs.undocumented_names(Threads))
+end