I think they are generally referred to as strike plates. The lock may have a brand name on it which will help you find a replacement.
I am guessing that you want to replace the existing one because it is covered in paint... if you sand it back, you might see a name. That said some one went the trouble of using a dragged paint finish over the top of it.
You might be ale to use meths to remove the (the added) paint finish- IF it was waterbased paint used initially. If the earlier coats were oil based then you can sand the whole lot back, polish it up and spray it with laquer, (cellulose thinners might remove the pint) but yeah, it is probably easier to find out who made the lock. if you look at the metal plate on the door side, it may help.
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