I think that an “Asset tab” would be great after selecting a device. That way one could plug in as much information he or she had on a particular device.
This feature would be especially helpful for someone that is trying to locate a physical device that is down on a campus with several buildings, floors, etc… and when the current documentation is old and wrong…
A DCIM/ IPAM would be a more suitable place for this (e.g netbox/phpipam) if you want to see it in Librenms then it would be better to integrate into those