[morcus]

I believe Starlark was renamed Skylark, even internally. Bazel is a build system that uses Starlark as a configuration language, not a fork of Starlark.

[westurner]

Bazel is an open source rewrite of Blaze (which introduced Skylark)

[adonovan]

Less a rewrite, more a variant: a majority of the source is common to both.