Copy Link Button / Copy Frame or Page URL per jscher2000

Copying the URL of the main/outer page

You've got options:

(1) Click the toolbar button (Shift+click for Markdown, Ctrl+click for HTML)

(2) Enable the optional in-address-bar button -- check the box on the extension options page

(3) Right-click in the page and use the "Copy Page URL" menu item (you can disable this item in the extension options)

(4) Use a keyboard shortcut of your choice -- set up your shortcut on the Add-ons page: https://support.mozilla.org/kb/manage-extension-shortcuts-firefox

Copying the URL of a framed page

Right-click in the framed page and use the "Copy Framed Page URL" menu item.

Inspired by https://www.reddit.com/r/firefox/comments/g9vgut/easy_way_to_copy_url_of_a_frame/ and https://support.mozilla.org/questions/1338122