ᴱQ. [xxʷ] became [f]; [xxʷ] > [f]

Reference ✧ PE12/020.3209

Order ()

After voiceless spirants become [x] before [x], [xʷ]
Before [f] became [v] except before stressed vowel

Phonetic Rule Elements

[xxʷ] > [f] ✧ PE12/020.3210 (xx͡w > ff > f)