How can I make a mouse-following floating window that shows contextual information when the user hovers over an element and certain conditions are met?"

Configuration Help & General Discussion
1

for example, one that appears when certain conditions are met while hovering

2

You maybe can do something like (far from ideal, but it is a starting point hopefully):

For floating menu:

image
image774×934 72.2 KB

For the actual trigger which will trigger the floating menu:

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image2910×1046 424 KB

however there will be some edge cases etc. which you need to handle I guess.

This will show my floating menu whenever Firefox is activated and also the hovered element contains "About" string.

By the way there's also the action "Show Custom Context Menu (NEW)" which is like a real context menu.