The source code of the editor Textmate2 is released under the GPL3 license at GitHub. TextMate 2 at GitHub.
Macromates says: “…This is partly to avoid a closed source fork and partly because the hacker in me wants all software to be free (as in speech), so in a time where our platform vendor is taking steps to limit our freedom, this is my small attempt of countering such trend…I am also a pragmatist and realize that parts of the TextMate code base is useful for other (non-free) applications, so I may later move to a less restrictive license, as is currently the case with the bundles.”
I’m surprised by this Textmate business. It’s curious and interesting.
Having tried Chocolat and Sublime my experience is similar to the author’s and between those two I too would choose Sublime, though it clearly doesn’t have that Mac feel.