You might find the Python discussion forums ([0] and [1]) interesting; conversation that guides the evolution of PEPs happens there.

As Nick mentioned, PEP 750 had a long and winding road to its final acceptance; as the process wore on, and the complexities of the earliest cuts of the PEPs were reconsidered, the two converged.

[0] The very first announcement: https://discuss.python.org/t/pep-750-tag-strings-for-writing...

[1] Much later in the PEP process: https://discuss.python.org/t/pep750-template-strings-new-upd...