Thanks to the capital P, Pello differs from the normalized name pello, so we can show where each of them is needed.
PEP 625 specified the sdist filename to be equivalent to the name normalized according to the wheel specification.
This means following these rules:
In distribution names, any run of -_. characters (HYPHEN-MINUS, LOW LINE and FULL STOP) should be replaced with _ (LOW LINE), and uppercase characters should be replaced with corresponding lowercase ones.
As a result, once a new Pello version is released, there won't be any uppercase Pello in the resulting specfiles.
A better example would be a one with hyphens and undescores, as this is the only difference between the project name and sdist name normalization.