Mozilla Foundation is a non-profit but Mozilla Corporation which develop Firefox is a for-profit entity.
There are other subsidiaries under the foundation umbrella like Mozilla.ai and MZLA/Thunderbird. This isn't something uncommon for large entity and there are many advantages. For example, it gives more freedom in term of decision making and spending to projects that aren't targeting the exact same consumer segment. Think about Thunderbird. Under Mozilla Corporation, it was always in the shadow of Firefox. Now, it's striving as an independent project.
There are other subsidiaries under the foundation umbrella like Mozilla.ai and MZLA/Thunderbird. This isn't something uncommon for large entity and there are many advantages. For example, it gives more freedom in term of decision making and spending to projects that aren't targeting the exact same consumer segment. Think about Thunderbird. Under Mozilla Corporation, it was always in the shadow of Firefox. Now, it's striving as an independent project.