htpasswd(1) on macOS
The text 4c622ad63a18, as Mac OS X 10.3.6, Mac OS X 10.3.5, Mac OS X 10.3.4, Mac OS X 10.3.3, Mac OS X 10.3.2, Mac OS X 10.3.1, Mac OS X 10.3 shipped it.
Create and update user authentication files
Flags it lists
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-b -
-c -
-d -
-m -
-n -
-p -
-s