Hello! I found some lines that should support GENDER.
```
"checkuser-userinfocard-menu-view-contributions": "View {{GENDER:$1|user}} contributions",
"checkuser-userinfocard-menu-add-to-watchlist": "Add {{GENDER:$1|user page}} to watchlist",
"checkuser-userinfocard-menu-remove-from-watchlist": "Remove {{GENDER:$1|user page}} from watchlist",
"checkuser-userinfocard-menu-check-ip": "Check {{GENDER:$1|user}} IP addresses",
"checkuser-userinfocard-menu-block-user": "Block {{GENDER:$1|user}}",
"checkuser-userinfocard-loading-label": "Loading {{GENDER:$1|user}} info",
"checkuser-userinfocard-error-no-data": "Unable to retrieve information for {{GENDER:$1|this user}}. Please try again later.",
"checkuser-userinfocard-toggle-button-aria-label": "Open {{GENDER:$1|user}} info card",
"checkuser-userinfocard-open-menu-aria-label": "Open {{GENDER:$1|user}} info card menu",
```