Brightness of the source mode: lydian 1, ionian 0 … locrian -5 (MODE_BRIGHTNESS; melodic minor -2, harmonic minor -3).
The chord holds a degree that sets the source mode apart from its reference scale (#4 lydian, b7 mixolydian, 6 dorian, b6 aeolian, b2 phrygian, b2 or b5 locrian…).
The borrowed chord, spelled in the source mode.
A usual borrowing (Open Music Theory, "Modal Mixture"). In a major key, the chords of the parallel minor (aeolian) on ii, iii, iv, vi and vii: ii°/iiø7, bIII, iv, bVI, bVII. In a minor key, the major tonic (Picardy third, from ionian) and the major IV of dorian. Never in a church-mode key, for which there is no established list.
Function of the chord in the home key.
Mode it comes from, on the same tonic: 'aeolian', 'dorian', 'mixolydian', 'harmonic minor'…
A chord borrowed from a parallel mode (modal mixture), from
Harmony.getBorrowedChords.