!has some special meaning either in travis or in YAML.
$ grep pyc setuptools.egg-info/SOURCES.txt
installis included in setup.py. Workaround?
project_urls. You can refer to the history, which may or may not make mention of that particular change.
python_requiresconfiguration item, and that seems to be parseable by SpecifierSet
Requirement.parse('python' + python_requires).specifiers
--script-dirargument, which I gather allows you to, at runtime, specify a target for all scripts.