Override page_section_header.tpl
Jamroom Developers
That would be a left-over then.
In the beginning select templates were allowed to be over-ridden. The way it was done was in each location where the template was about to be called, there was an if/else check to see whether a template of the same name was in the active skin directory.
Then that if/else check got moved into the template parser function so modules didnt need to specifically go look for it. (just in case some module developer forgot to include that if/else and made it impossible to override.

)
So what your seeing is some left-over code that allows you to use the same name.
Safer to use the correct over-ride naming convention.
One other example is 'admin.tpl' is still being looked for currently. Its extra code that might go away in future. So 'jrCore_admin.tpl' is safer.