Hi,
The search system works using Github own search REST API, and is actually looking into the code of these actions, not just the title. iI's been like that since day one.
On top of that, when I produce custom actions, I usually decorate the manifest with additional keywords. This manifest is also present in the code of the custom action as a comment, so it gets picked up by Github api.
"Space" is a unity api keyword using in many many scenarios, to define local and world referencing for positioning or rotating, so you will find this in almost every actions that will try to move or rotate a gameobject, which isn't going to help you find a particular action unfortunatly. this explains why you get lots of action that "position" a gameobject.
I hope it make sense

Bye
Jean