In Fedora a license has been submitted for review that seems to match
HPND-sell-variant except that the word "appears" in HPND-sell-variant
is "appear" in this license.
https://gitlab.com/fedora/legal/fedora-license-data/-/issues/63

My prescriptivist English grammar is rusty but I think this can be
interpreted as a difference in English verb number as well as possibly
a difference in manifestation of a subjunctive that I would expect to
see vary between British English and American English.

Looking at the SPDX Matching Guidelines, am I right in concluding that
the guidelines don't address formally-minor English grammar
differences of this sort?

Richard