Probably all they had on hand. For such emergencies, I carry a pair of normal brass hose barb unions in 3/8" from a closeout store that I got for cheap that originally came some auto parts store. It never hurts to have such spare parts, they don't take up much of any space. I could probably make them fit 5/16" hose for the return system in a pinch.Just looks like someone used a push-lok fitting to splice the two hoses.
Out of curiousity do you know what pressure the push-lok style fittings are good for?The yellow plastic piece is just meant to stop the hose when you push it on as this type of rb requires no clamp. As Russ/Typ4 stated above, putting a clamp on that style barb is a no-no and will cut the inner tube.
In fact if you clamp them that sharp edge cuts the hose liner and then eventually it leaks. As told to me by a reputable Parker representative which happens to be on this forum.