FTR, 3.0 is actually a valid channel string, it defaults to 3.0/stable. /stable/ubuntu-{19.04,18.04} is technically not valid, but refresh api actually parses it ok, even it it's actually the wrong value (should be 3.0/stable/ubuntu-19.04)
FTR, 3.0 is actually a valid channel string, it defaults to 3.0/stable. /stable/ ubuntu- {19.04, 18.04} is technically not valid, but refresh api actually parses it ok, even it it's actually the wrong value (should be 3.0/stable/ ubuntu- 19.04)