Not a Firefox browser/Mozilla issue.

Sorry, the EndNote Click extension for Firefox is not currently available from the Mozilla Add-ons site. I found a note about it over on the Discourse site saying as of November 2024, the developers are working on bringing it back: https://discourse.mozilla.org/t/endnote-click-where-has-it-gone/136981 That sounded promising, but apparently it's been missing since May 2024 or earlier, according to this Reddit thread: https://www.reddit.com/r/firefox/comments/1cmdjy6/endnote_click_removed_from_firefox/ Can you contact EndNote support and ask whether they are distributing it directly or when you might be able to get it? That would be safer than using random links to other websites, although that might be the next thing if this is a really important tool (I've never used EndNote myself).