[QGIS-Developer] where do I find QEP #17 ?

[Sandro Santilli]

A comment on top of src/core/qgsinterval.cpp recommends
to read QEP #17 to find detail about criticality of
the QgsInterval class, but how do I find QEP documents ?

I don't find it in
https://github.com/qgis/QGIS-Enhancement-Proposals

--strk;