Is this a variant of the "Saved Info" feature? Cause ChatGPT's equivalent feature is automatically added, so Gemini might have been copying that behavior for personalization. In my heavy experience with Gemini 2.5, the Saved Info was the major (if not only) source of observable contexts so that might be the case here.

By the way, Saved Info contexts contain the date of info lines added for an unclear reason. Automatically Saved Info might be the answer if that is used for prioritization.