I can't translate the tooltip "Insert/edit link" for the link icon in TinyMCE 6. (see screenshot)

Edited to add:

The string tiny:insertedit_link in editor_tiny.php can't be translated in AMOS because strings which end in _link follow a convention:

stringname_link - an optional string naming a path in Moodle Docs, only if required, calculated just like the link in the footer to go to the right language etc, and shown after the help text in the popup as a link with an icon to "More help...". These strings don't need to be translated, so are hidden in the AMOS UI.

(from https://docs.moodle.org/dev/String_API#Help_strings )

However, on investigation, it turned out that many plugins include _link strings which  don't follow this convention and require translating.

Solution (as discussed and agreed in the comments below):

1. Unhide _link strings in the AMOS UI so they can be edited
2. Populate language packs with a copy of the English original for all _link strings, unless such a translation already exists.

This solution allows for _link strings in TinyMCE, BBB and other plugins to be translated. Also, help links can be edited, allowing for localisation of internal docs.