Hallo Andreas,
dazu habe ich dies gefunden:

Default User IDs used by server: QTMHHTTP and QTMHHTP1 (for CGI programs)

Default Subsystem for HTTP server jobs: QHTTPSVR

Library that contains HTTP server code: QHTTPSVR

Configuration files: QUSRSYS/QATMHTTPC and QATMHINSTC - see QHTTPSVR library for special ADMIN instance configuration files.