Scala
Scala is a file format for storing information about tuning systems. Live 12 uses an extended Scala format.
You can learn more about Scala at the Scala Home Page, where you can read the specification for the file format, find a partial list of supported software, and download a large archive of Scala files. You can also read the specification for Ableton's extension of the format.
Interactive Scala editor
The pages on this site include widgets like the one below, which include a Code tab where you can experiment with Scala files. Your changes will be reflected in the tuning of the notes in the Sequence tab and on the pads in the Play tab. You can also export your edited Scala file.
Some tips for using the editor
As you move your cursor to different lines in the code editor, notice that text appears underneath that provides information about the line. The editor will help you as you edit; errors that will cause the file to not work will appear with a special warning symbol.
When you place your cursor in a line that specifies a note's tuning, you'll hear the note play briefly. You can also lock notes on by pressing the buttons to the left of these lines. You can use this to precisely tune certain intervalsAn interval is the distance between two pitches. It can be measured as a ratio between their frequencies or in cents.Visit the link to learn more, for example.