ID — programmed personality .
?: A what now? -- A "programmed personality" does not literally mean a programmed personality nor does it refer to things like alters or etc, it refers to making a version of yourself you want to become, then over time molding yourself into that desired version of yourself. It's called "programmed" because you created it, kind of like how you "create" when programming/coding something. [definition wording may change I suck at wording.]
?: Why is it called a "ID"? -- Because there isn't a real term for it, so ID which stands for identity is the closest you get. "I ID as/with this."
?: Why does it need a flag? -- For fun and whimsy. It's really not that deep, there's flags for all sorts of "useless" and non-LGBTQ+ stuff out there.
?: Flag stripe meanings? -- None, I just messed around. Hoe life or no life.
Anyone can use, No DNI. ALT flags allowed/welcome.
Possible advice for said ID: link