3.9
bpo-35808: Retire pgen and use pgen2 to generate the parser (GH-11814)
Allow pgen to produce a DOT format dump of the grammar (GH-18005)
Fix typo in the parser generator (GH-18603)
bpo-11410: Standardize and use symbol visibility attributes across POSIX and Windows. (GH-16347)
Refactor Parser/pgen and add documentation and explanations (GH-15373)