It has the characteristics of a CGA card. What did you plug it in to?

Into the composite plug of my sony trinitron TV (as I live in france, I may build a cga to scart adapter,, it seem to be compatible)

And into which computer? 😀

The 8088 that I'm currenrly repairing ^^

There are DIP switches on the motherboard. Do I have to ajust them ? (Also I've not seen any card that looked like a graphic card, can my RTC card also be a cga card ? There is a 9 pin connector on it (it may just be a serial port though)

Yes, you usually need to set dip switches on the pre-AT systems.

Very weird, the two RCA connectors were common in EGA cards and they didn't output composite video, so I was about to throw in the idea that this might be an EGA card. But neither the feature connector nor configuration jumpers/switches exist. I'm curious to see what exactly it turns out to be...

Since I'm very new to 8088 stuff (I never touched one before the last two days 🤣) where should I look to know how to configure them ?

You can hope that the switches are IBM compatible (can't see any on your photos) and set them alike:

http://www.rci.rutgers.edu/~preid/pcxtsw.htm

Updated the topic with better photos. It doesn't seem to be ibm compatible sadly

There are a bunch of broken resistors on the card as well, directly below the COmposite-styel connectors.

These are small, not broken.

Try to change the dip switches 5 and 6 to off and on. Currently it's setup for monochrome video (if it matches IBM).

Well without touching anything, when I tried the vga card it worked directly. And yes I've tried the 4 possible positions and nothing came out from the card 😒

I think the best thing to try before is the RGBi output, but I have to build the adaptet first