@PeterJones said:

[IANAL, and I don’t know the legal term for a non-registered trademark]

An unregistered trademark, sometimes informally called a common law trademark, is an enforceable mark created by a business or individual to signify or distinguish a product or service.

–For future reference.

The stronger case needs to be made as you mention to differentiate what could be called a trademark name versus a generically descriptive name. Such as the difference between Borax as a chemical and Borax as a trademarked product name. I am not a lawyer [IANAL], either, but I have done legal research from time to time, on these types of subjects as well, in the past.

I see pending pull request from 2022.

Yep. It appears the owner @morbac hasn’t touched that repo since 2022. But the @epilogic-ch group at GitHub, which seems to be affiliated with @morbac, has made a couple of commits about a year ago, so it’s not completely abandoned.

If repo is not maintained someone should take over maintenance.

“take over maintenance” is not something that should be arbitrarily done. The code is GPL-3, which means anyone can use the code as long as giving credit to @morbac. But names of software projects are technically not part of the GPL-3. Names can be trademarked – registered or just effectively – and you cannot use the name without specific permission. (If you can show years of consistent use of a name as a “trademark”, even without using ™, then you can get and protect the “effective” trademark [IANAL, and I don’t know the legal term for a non-registered trademark]; XMLTools probably has enough history that the name is effectively trademarked to @morbac, but your interpretation and mileage may vary.)

So, if you reach out and get permission from the current owner, you can definitely take over the code and name. (That’s been done with some plugins – sometimes, they even just give you commit-permission in the original repo, like was done for PythonScript).

If they don’t respond or give permission, then another option is to fork the project, give it a new name, and publish it starting from the same codebase but under the new name (making sure to give proper attribution of where it was forked from). That’s happened, with a lot of the Markdown plugins in Notepad++. If you think you have the skills and the willingness to support the plugin under a new name, then great, go ahead and do that.

But to just fork a repo, and then take over publishing under the original name is on legal/moral/ethical shaky ground, and I wouldn’t recommend it.