MarsSeed [1] filed a deletion request for libopenblas [2]:

This has not been needed for quite some time, as Arch repo carries
openblas, including its libs, and it can be installed side-by-side
with blas.

[1] https://aur.archlinux.org/account/MarsSeed/
[2] https://aur.archlinux.org/pkgbase/libopenblas/