I was going to ask but I figured it out, DFL = Democrat Farmer Labor party. (It’s why you love Minnesota DFL).
The Democrat Party wasn’t near as extreme left as Minnesotans, so they started their own party that just associates with the national Democrats.
Yes, the Farmer Labor party were once a separate outfit before merging with the rats in 1944. It’s been the DFL ever since.
In next door North Dakota there was a similar phenomenon with the “Non-Partisan League” which went from a socialist RINO faction to merging with the democrats in 1956. They still use the name as well.
Prairie radicals, gotta love them.