guitar scale
E♭ Mixolydian
E♭1F2G3A♭4B♭5C6D♭♭7
Major with a flattened seventh: the scale that fits a dominant seventh chord without altering it.
The same sounds spelled from the other side are D♯ Mixolydian.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
E♭WFWGHA♭WB♭WCHD♭WE♭
What is true of it
E♭ Mixolydian is E♭, F, G, A♭, B♭, C and D♭, and back to E♭.
Its steps are W – W – H – W – W – H – W, where W is a whole step and H a half.
On the same tonic, E♭ major differs from it by exactly one note.
Across the first twelve frets of the guitar its notes fall in 43 places, which is what makes a scale a shape rather than a list.
Chords made only of these notes
Found by testing every chord in the catalogue against these 7 sounds, not chosen.