Embarrassing: 986 Key battery change - how to

[BRAN]

...on a 986 key WITHOUT transmitter. I'm kind of clueless how to open it, tbh….lol.
The case is a little DIFFERENT, so the regular infos on the web don't help. Btw. the battery is just for a little key light and not really necessary, but I feel challenged how to open it.
Anyone?

[particlewave]

This should be the same:

https://www.pelicanparts.com/techarticles/mult_keyhead/mult_keyhead.htm

[BRAN]

EXCELLENT, particlewave!
I already tried to press that little plastic button in...actually so hard that it left scares in it. I guess, I need an exact dimensioned tool to pry it in, been sitting there for 20 years.
Anyways, thanks again, I was on the right track.