Good answers in here. It looks like a NO maintained push button to me.
One good thing about IEC drawings is they're very standardized. Having seen european equipment from 40 years old to brand new, the newer stuff is extremely consistent in the way it is drawn. They do over abbreviate though and a lot of the symbols make no sense e.g. their flow, float and pressure are dumb. Another example is the timing relays. You just have to know the symbols wheras NEMA will tell you NOTO, NOTC etc.One more reason to hate IEC style of drawings:
No full description next to the symbol.
The description on drawings should match the description on the tag/label on the machine.