Handle special URLs, avoid hard coding

[hanguokai]

In browsers, there are some common URLs that developers(users) want to open or detect. Currently developers can only hardcode these URLs. But different browsers may have significant differences.

The goal of this issue: It would be helpful if there was a consistent way to judge or open these URLs without hardcode.

This issue covers #470 which is just one of these special URLs.

	Chrome	Firefox	Safari
New Tab	Chrome chrome://newtab/ Edge edge://newtab/ Opera chrome://startpageshared/ Vivaldi chrome://vivaldi-webui/startpage	about:newtab	favorites:// topsites:// (Legacy)
Homepage	No URL	No URL	No URL
Default homepage	No URL	about:home	No URL
Extensions management	chrome://extensions/	about:addons	No URL (In browser settings)
Extensions shortcuts	chrome://extensions/shortcuts (for all)	No independent URL (In about:addons)	-
Extensions details	chrome://extensions/?id=ext-id	No independent URL (In about:addons)	No URL (In browser settings)
Browser history	chrome://history/	No URL (In a independent window)	history://
Browser bookmarks	chrome://bookmarks/	No URL (In a independent window)	bookmarks://
Browser downloads	chrome://downloads/	No URL (In a independent window)	-
Browser settings	chrome://settings/	about:preferences	No URL (In a independent window)

Some use cases:

• Determine whether a tab is a new tab page, or a bookmark page, etc.
• Open the extension management page
• Open this extension's details page for toggling "run in incognito mode", "site permissions", "allow access to file URL", etc.
• Open shortcuts page for setting shortcuts.
• Open browser history, browser download or browser settings page.

Another special case: the extension's store link or review link. Developers have recently discussed it. The link needs to be modified to a specific store link before each release. It is best that browsers support open this page (if the extension is not from a store like unpacked extensions or self hosted extensions, just ignore it or throw error).

To solve these problems, a flexible API is needed, and different browsers can support parts of functions.

[fregante]

Likewise, it would be nice to find non-scriptable HTTPS URLs like the ones in the Chrome Web Store:

• https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Content_scripts
• https://stackoverflow.com/q/11613371/288906
• https://github.com/fregante/webext-content-scripts?tab=readme-ov-file#isscriptableurlurl

[dotproto]

I've updated the table in the original issue description to include the user's current homepage and the browser's default homepage.

[Rob--W]

FYI in Firefox the meta-bug tracking requests related to opening special pages is at https://bugzilla.mozilla.org/show_bug.cgi?id=1269456

[carlosjeurissen]

The ability to open the extension shortcuts page has been discussed here:
https://groups.google.com/a/chromium.org/g/extension-api-reviews/c/4Odm0D9FR_E

https://bugs.chromium.org/p/chromium/issues/detail?id=1173375

#126