Understanding tuning

I came across this video (please see below) that is helpful for me as it explains the way the pitches of the 12 notes are determined. Harmonicas are tuned “Just Intonation “ and “Equal Temperament.” This video uses pictures and pitches displayed and played to better understand the difference.

I’ve read that the Golden Melody has equal temperament. The others, I’m also told, don’t and I am curious about the other models and the subtitles.