Arvados

/opt is the standard place to install add-on software that wants to stay separate from the standard hierarchy. Installing here would help administrators by more clearly communicating what's in the directory, and playing nicer with existing partitioning schemes, backup policies, security directives like systemd's/SELinux, etc. /var/lib is meant to include user-generated data only.

Purpose of /opt
Purpose of /var/lib

Examples of other software that does this include RT (in the default configuration for source installs), WebEx, and Zoom.

A nice follow-up would be to separate having static software and data in /opt while putting user-generated data under /var/lib or /var/opt .