MarsSeed [1] filed a deletion request for python2-corner [2]:

As python2-sncosmo has been deleted, this helper module has no use anymore on AUR.

Supernova Cosmology packages support Python 3 only, so there is no point in keeping defunct Python 2 libraries around.

So I suggest deletion. AUR has the Python 3 variant of this and of sncosmo.

[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/python2-corner/