What is the purpose of the 'u' column in admin.db?

[goodmami]

The u column in the admin database is populated with the name of the script creating the database:

OMW/scripts/load-admin-users.py

Line 25 in 7bd65ed

u = sys.argv[0]

But the schema says it should be an integer value:

OMW/omw/schemas/admin.sql

Line 19 in 7bd65ed

u INTEGER NOT NULL,

It seems the meaning of this column may have drifted over time. What is the intended value and what is it used for? (one problem with one- and two-letter column names is that GitHub won't show search results in the code)