Man pages matching name __pmprocesspipe in section 3:

__pmProcessPipe.3.en	debian 10 / libpcp3-dev
__pmprocesspipe.3.en	debian 10 / libpcp3-dev
__pmProcessPipe.3.en	debian 11 / libpcp3-dev
__pmProcessPipe.3.en	debian 12 / libpcp3-dev