The $SAGE_ROOT/upstream/ accumulates tarballs over the time. The proposed sage --package clean command cleans that directory and keeps only tarballs that are currently needed (i.e. only the versions indicated in $SAGE_ROOT/build/pkgs/*/package-version.txt are kept).

Component: misc

Author: Thierry Monteil

Branch/Commit: 3809a6f

Reviewer: David Coudert

Issue created by migration from https://trac.sagemath.org/ticket/34490