Custom asset selector

I've been googling around for this answer for about a day, but I can't find anything mentioning it.
Is it possible to override the asset selector window, or extend it with custom code?

 

I had the same question some weeks ago... I reverse engineered unity to see how the object selector window is implemented.
Unfortunately there are classes marked as internal which would have been needed to replace the existing selector window.
So, the answer is: No, it is not possible.

What might be possible, though: You can write custom property drawers for certain types which can replace the default ones. They probably can open your own asset selector window...
However, you would need to do this for every kind of asset you want to support. Also, it will probably clash with other assets which have custom property drawers for the same types.

 

Ok it sounds like it would be too much work.
Thank you for the answer!