No idea. The server git does maintain snapshots of each release. So you could compare the code for the DLNA plugin vs the 10.8.z branch of the server which still had DLNA built in.
Jellyfin 10.10.3 (Docker)
Ubuntu 24.04 LTS
Intel i3 12100
Intel Arc A380
OS drive - SK Hynix P41 1TB
Storage
3x WD Red Pro 6TB CMR in RAIDZ1 (JF Library)