Research how `*_proxy` environment variables are used in various tools
This issue's purpose is for me to gather the most important bits of information regarding
*_proxy usage in various tools and languages.
So far I've researched
These by themselves demonstrate the inconsistency with regards to using
*_proxy through environment variables.
As such, the only conclusion I can draw at the time of writing is to always provide the lowercase and uppercase variant, and to ensure that its values are not different due to precedence differences.