I’m not familiar with this library and have never used it, but with a quick search online I found Robot Framework TestFX Library
Indeed the library doesn’t seem to have been updated since 2018, but this might no be all bad if there’s no issues/bugs and it still works then there’s no need to update it
It talks about using jython or remote library, as robot framework no longer supports python 2.x and there’s no python 3.x version of jython, you’ll need to use the remote library method, and this could be why there’s been no need for updates?
That’s everything I can offer, hopefully it’s helpful, and maybe someone else can pitch in with more info