The bolt tension spring is held in a place by a dovetail.

The rear end of the spring is dovetailed and slides into the corresponding cut in the frame.
What holds it in place from coming forward and out of the cut and what you have to by-pass to remove it is a small lug or extension on the bottom of the spring towards the front.
That lug sits behind the dead-ended cut in the frame so when the spring is in place or only slightly raised (as in when the bolt snaps past it,,the spring can't come out of the cut.

To remove, you have to carefully pull/pry the front end of the spring outward (to the right),,flexing the spring enough to clear that small lug on it's back-side. Then holding it out there, pull it forward and out of it's dovetail cut.
The Luger pistol uses the same idea in it's one piece spring/ejector and is held in place and removed the same way.

Flex it outward just enough to clear that lug,,no more. You risk breaking the spring if you pull it out too far of course. No need to anyway.
Sometimes it can be pulled part way forward and then it needs to be carefully tapped the rest of the way free from the back end.
Brass punch, polished tip small screwdriver, padded /smooth jaw pliers, ect.
It's not impossible,,they installed thousands of them and removed probably as many.

I've taken many of them out and put them back in w/o any issues. Just respect the part as a spring and don't bend it any farther than you need to to remove or re-install.