I’ve just seen a 2017-old discussion on fr.wp village pump where people say they didn’t unederstand “Updated since my last visit” messages, believing those were diff comments.
They proposed to turns “my last visit” into “your last visit” to avoid confusion and for consistency with other MW messages which rarely (never?) use first person (e.g. in preferences: “your signature” and not “my signature”).
In core, the message key/value can be found here: https://gerrit.wikimedia.org/g/mediawiki/core/+/07a883388adb76bef1e760ea9d87db3c1f04ff74/languages/i18n/en.json#172