Three characters on the .org, symmetrical, with the digit in the middle. Palindromic domains are a recognised category with their own collectors, because symmetry is pleasant to look at and easy to remember.
The letter-digit-letter shape also types quickly and holds its form at any display size. An icon, a badge, a stamp, a favicon. E7E reads correctly in all of them, which is not true of longer names that get compressed into illegibility.
With no fixed meaning attached, the name is entirely open. An organisation whose initials fit, a foundation wanting a compact mark, a technical body, or a project that simply needs something short and distinctive.
The .org adds institutional weight that a three-character string wouldn’t have elsewhere. Short plus .org is the shape established bodies use, and the ordinary combinations disappeared decades ago.
Symmetrical, short, and there is exactly one of it. Enquiries welcome.