JF Mezei asserted that:

However, in the landing video from within the engine cavity, one sees a
lot of yellow flanes starting as it nears the ground. Is this because
below a certain thrust level, the egines are less efficient? or is the
yellow just imporities near ground that are buened by the clean output
of engines?

There was also yellow in the brief external camera shot. But ISTR that
Falcon 9 stage 1 return and landing burns look similar, as the
slipstream pushes the flames up and around the stage.

/dps


--
"What do you think of my cart, Miss Morland? A neat one, is not it?
Well hung: curricle-hung in fact. Come sit by me and we'll test the
springs."
(Speculative fiction by H.Lacedaemonian.)