Have a nice custom integer field, like this one for Maniphest:
{
"mycompany.estimated-hours": {
"name": "Estimated Hours",
"type": "int",
"caption": "Estimated number of hours this will take.",
"search": true
}
}
You can reproduce T15752 before the change. It just works after the change.
Or, just trust your instincts by looking at the same method in PhabricatorStandardCustomFieldLink.
Also, use the "normal" frontend search page. Still works as usual.