Very interesting! Works good for already installed games and downloads good game information.
I am little bit concerned to give username and password for importing not installed games, but its open source and if after some time there are no complaints I will try that too.

Hopefully. Well that is a tool that finally could replace my custom spreadsheet where I so far noted down all my games with annotations like "never again" or "want to play next".

The thing with Steam since they made the game library set to private by default, a lot of people don't list them anymore. Your game library needs to be set to public, if only temporarily enough for it to import the data. so yeah, make sure your game library is set to public, import, and then you can set it back to private if you want.

This means you would have to do that again and again every time you buy another game on Steam. I guess, no solution is perfect.

I currently have Lutris. I don't have a number of games installed to make it useful, but I do like occasionally using it.

I like tracking how long it takes me to play through games and record them on howlongtobeat.com, so I like that Playnite lets me easily track playtime of non-Steam games. I don't use GoG Galaxy, and I have some games from back when I used Direct2Drive and Gamersgate that I've been trying to finish. So this is helpful for those. And it's just nice to have a single launcher.

I haven't needed to give it any credentials, either.

I gave it a try (too many bloody shops, I now need to avoid overlaps), but I'll uninstall it for the following reasons :

1) Not compatible with Gamersgate and Humble. So, kinda useless to me.

2) Imports gog game summaries in german for some reason.

So, yeah, not there yet. At all.

For some reason, if I have this running, it will mark random forum threads and all announcements as read.

I haven't given it any information to login anywhere.

I downloaded the zip file, not the installer.

I am permanently logged in through the browser, but that's a completely unrelated program. Or app, as the kids say. I'm also permanently logged in through Galaxy, but again, this should not be accessing any info of my account if it's set to import already downloaded games only.

This being open source, someone who knows how to code might want to check what the hell this program is doing, accessing what it shouldn't be.