Prefixes like that are typically created to indicate code from a specific project, product line or company. Over time, when coding practices are shared across projects or product lines, or after mergers an acquisitions, the original acronym gets lost or no longer fits. Creative minds then usually find a backronym to provide a rationale to keep using it.
In short: it is a good question, but it is best to just take them for granted. Nobody knows, cares or wants to share.
