MarsSeed [1] filed a deletion request for jdk-devel [2]:

Orphaned package, last updated in 2018.

It was based on Oracle Java 11 Development Kit preview version.

According to a comment in 2019, since that time Oracle requires login to access insider builds.

There were no answers or newer comments since that time.

As I remember, Oracle kept only a very small subset of mostly legacy corporate addon technologies behind closed doors, and they abandoned new closed feature development on Java.

I think it's safe to delete this legacy package because it is defunct and there seems to be zero interest in it since 2019.

[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/jdk-devel/