Comment (by Roland Haas):

Note that the ET thornlists no longer refer to svn.cactuscode.org as all ExternalLibraries have been moved to GitHub.

The issue with svn.cactuscode.org (#2069) and svn.einsteintoolkit.org (#2262) using no longer supported OpenSSL library versions persists though and affects older thornlists as well as some (few) repositories that only exist on those svn servers.

--
Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2415/cannot-checkout-svn-repos-with-ubuntu-2004