The UI confs are IDs for the Kaltura widgets, i.e: player, upload widget, etc.
If you want to get all UI conf objects/records that represent players for a given partner programmatically, you can use the uiConf->list() API, passing objTypeIn=1,8
Where 1 is the value for the PLAYER constant and 8 is the value for PLAYER_V3 constant [i.e HTML5 players]. You can also filter based on player tags, using tagsMultiLikeOr and tagsMultiLikeAnd.
For instance, when adding a player via Studio, the following tags are set: ‘html5studio,player’.