Some requests allow for specifying timestamps or generate timestamps with time

zone information. We apply the following rules, in order of priority, to

determine timezone information for API calls.

For API calls that allow for a timestamp to be specified, we use that exact

timestamp. An example of this is the [Commits API](/v3/git/commits).

These timestamps look something like `2014-02-27T15:05:06+01:00`. Also see

[this example](http://developer.github.com/v3/git/commits/#example-input) for

how these timestamps can be specified.

It is possible to supply a `Time-Zone` header which defines a timezone according

to the [list of names from the Olson database](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones).

$ curl -H "Time-Zone: Europe/Amsterdam" -X POST https://api.github.com/repos/github/linguist/contents/new_file.md

This means that we generate a timestamp for the moment your API call is made in

the timezone this header defines. For example the [Contents API](/v3/repos/contents/)

generates a git commit for each addition or change and uses the current time

as the timestamp. This header will determine the time zone used for generating

that current timestamp.

If no `Time-Zone` header is specified and you make an authenticated call to the

API, we use the last known timezone for the authenticated user. The last know

timezone is updated whenever you browse the GitHub.com website.

If the steps above don't result in any information, we use UTC as the timezone

to create the git commit.