`USES=python:env` can be used when the variables exported by the framework are needed but a dependency on Python is not.
It can happen when using with crossref:uses[uses-shebangfix,`USES=shebangfix`], and the goal is only to fix the shebangs but not add a dependency on Python.
+[[uses-qca]]
+== `qca`
+
+Possible arguments: (none)
+
+Handle dependency on the package:devel/qca[] crypto API.