Is it the one with 5 users and zero reviews? Unless you know the author personally or by reputation, or can read/assess code, I would not install it.

More generally: Tips for assessing the safety of an extension

What problem are you trying to solve?

Thanks. No I don't know the author personally and I don't read code, so I think I may have to give this a pass.

What I want to do is to copy an entire Claude chat (conversation) and move it to a Project (in Claude.) The options aren't very good (time intensive and difficult) so the add on solved the problem (if only I could be sure of the security.)

The specific conversation I need to put into a Project file is because the work was not complete but it had reached Claude's usage limitations (so either have to move it to a project or start a new chat (basically start over by pasting pertinent content from the previous chat, and then risking reaching a new limit barrier because it is actually a project rather than a conversation (which I didn't realize until I'd already begun it.)

Do you have any other suggestions?

I am not familiar with Claude Projects.

If this extension is necessary, you could create a new profile for the purpose of using it so it doesn't have access to any of your browsing in your regular profile. Here's how:

One method to suss out an issue with settings or add-ons is:

New Profile Test

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Take a quick glance at the page and make a mental note of which Profile has this notation: This is the profile in use and it cannot be deleted. That is your current default profile.

Click the "Create a New Profile" button, then click Next. Assign a name like ClaudeOnly, ignore the option to relocate the profile folder, and click the Finish button.

Firefox will switch your default profile to the new one, so click the Set as Default Profile button for your regular one to avoid an unwanted surprise at your next startup.

Scroll down to ClaudeOnly and click its Launch profile in new browser button.

Firefox should open a new window that looks like a brand new, uncustomized installation. (Your existing Firefox window(s) should not be affected.) Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system to get a clean test.

Install the extension.

Sign in to Claude and try what you need to do.

When you are done, you can close the extra window without affecting your regular Firefox profile. (ClaudeOnly will remain available for future use of the extension.)

Hey, that's a really interesting workaround. I didn't realize it was an option. Let me think about this before I attempt it. If I use this method, what do I do about the "2nd Firefox" afterwards? (That is, after I have completed the tasks I need to accomplish in Claude?)

You can keep that profile for future use and just start it/exit it when needed.