removing and adding dynamically assigned system users

[Othmar Pasteka <pasteka@kabsi.at>]

hi,

i am currently building a package which needs a system user. so i
use dynamically assigend system users (range 100-999). i install
it with adduser --system etc.
now, when a package is deinstalled, when is the user removed from
the database ? when postrm remove is called or is it postrm
purge? i don't know and couldn't find hints sofar in the docs.
maybe i oversaw something.

regaards
Othmar