A Phrygian mode
A B♭ C D E F G
Formula: 1 ♭2 ♭3 4 5 ♭6 ♭7
A minor scale with a minor 2nd, a semitone above the root: the darkest colour of the minor modes, common in flamenco and metal.
It has the same notes as F major, starting from A.
On the neck, frets 0 to 12
The 1st string (high e) is at the top, as in the app. The root is filled.
Open it in the app: 3. Scales & Modes, in A
The Phrygian mode in other keys