One odd exception is GitHub which inexplicably uses size-8 tabs by default which is way too big. I can only assume that somebody there is a space zealot and wants to screw up the UX for enlightened tab users.
http://blog.gngcreative.com/wp-content/uploads/2015/02/mi0fg...
Those metal things you can see there, those are tabstops. They are called tabstops because when you press the tab key, the carriage mechanically stops at the tabstop.
Tabstops were placed every 8 characters. A tabstop is simply a way to "type" 8 spaces with one keypress.
Github is not the only page that uses 8 spaces for a tab, and it's definitely not inexplicable. The Unix/Linux terminal uses 8 spaces by default if you insert a tab. Vim uses 8 spaces by default if you insert a tab. Python considers a tab to be equivalent to 8 spaces. I'm sure there are a lot of other systems that default to this value.
If you want to control how an indentation looks, use spaces. If you want tabs because the size is configurable and can be adjusted to one's preferences, you can't at the same time complain about "unreasonable configurations" that others use :)
tabstops were _not_ restricted to 8 characters. In many systems different tabstops were different widths from their predecessor. E.g. your first tabstop might be 20 characters in but all the ones after it would be 8 past their predecessor. Alternately you could vary all of them but that'd look pretty weird.
When I have to work on N platforms that are constantly shifting, I don't want to spend the overhead and mental effort to reconfigure the ones that can be reconfigured, and eat nameless dread on the ones that can't.
When you view code across dozens of platforms, across dozens of machines, your perspective on "high maintenance config" everywhere changes a bit.
If you can't be effective with default configs, you lose efficiency to config maintenance.
Really, the last thing I want to deal with while I'm triaging some critical issue is dependency management for N code viewers.
root = true
[*]
indent_style = tab
indent_size = 2
This can be very neat for responsive design: use tabs for your indentation, and then on large screens use `tab-size: 4` because you’ve got space to spare and four is generally superior to two, and on narrow screens use `tab-size: 2` because you don’t have as much width to play with.