QEP's (QGIS Enhancement Proposals) are used in the process of creating and discussing new enhancements for QGiS.
Currently Github is used to centralize the discussion and edit's to a proposal.
To see actual proposals, go the the 'Pull Requests' in this repo (somewhere ==> there to the right).
There you see current open proposals and/or the closed ones.
Now click on the 'Files changed' tab to see the rst file in which the proposal is written (file is probably named like 'QEP-xx-my-proposal.rst'). To view it in a more readable way, click the button 'View'.