C1DEFLTS parameter E2ELOGMBR value is stored in endevor control blocks during endevor initialization by program BC1PINIT.
This happens at the start of the ISPF endevor or QE dialog, at the start of any batch utility like C1BM3000, or at the start of an STC spawned at the request of CAP, workbench or Web Services. Note that, in the case of Web Services, the use of STC pooling has an effect on this since endevor initialization happens at the start of the STC.
If the member name was specified, it is read and parsed at the end of the first element or package action performed during the endevor run, right before the point where any defined user exit 03 would be called or, for package actions, after any defined "after package action" user exits would be called. If the member parses without error, then E2E logging is performed for the action as specified in the member.
The E2ELOGMBR member is not parsed again during the same run. Subsequent element or package actions are logged at the same spots using the definitions parsed at the completion of the first action.
This is how our programs are written as of today.
Hope this helps
Eduard Penafiel
CA-Endevor support