Some historical context, from https://bugzilla.mozilla.org/show_bug.cgi?id=1602293#c0 (for a clone of the extension):
… S3.Translator. was removed because it offer (optional) to send every visited URL to 3rd-party server. …
From around a year ago, three Wayback Machine captures of AMO pages for the extension. In chronological order (note, the 2018-11-12 step down from 6.19 to 5.35):
https://web.archive.org/web/20181002173137/https://addons.mozilla.org/en-US/firefox/addon/s3google-translator/ version 6.18
https://web.archive.org/web/20181112164625/https://addons.mozilla.org/en-US/firefox/addon/s3google-translator/ version 6.19
https://web.archive.org/web/20181121182443/https://addons.mozilla.org/en-US/firefox/addon/s3google-translator/ version 5.35
Captures of privacy policies:
If user consent is given, this add-on will show advertising on web pages.
In that case, the user’s browsing history can be accessed by a third party (ad network).
This behavior does not extend to Private Browsing mode.
ADVERTISEMENT DISABLED BY DEFAULT!
If user consent is given, this add-on will collect non-personalized browsing history.
In that case, the user’s browsing history can be accessed by a third party.
But we don’t collect cookies, password, e-mails or any other confidential info.
Only the domains (not full URLs) of the web-sites visited and nothing else.
https://bugzilla.mozilla.org/show_bug.cgi?id=1602293#c1 two days ago:
I’ve reviewed the add-ons and confirmed they are collecting ancillary user data against our policies.
Chrome Web Store
Today, for version 6.25, with added emphasis:
Collection of statistics:
If user agree, then the extension may collect non-personalized browsing history.
Such statistics are needed to improve this extension – based on domain names, a map of work priorities will be drawn up in which area it is necessary to add efforts to make the extension better.
We don’t collect cookies, password, e-mails or any other confidential info.
Only the domains (not full URLs) of the web-sites visited and nothing else!