Hi, we added them based on your instructions that you wrote me before.
plugin > template > job > search-job-filter.php
plugin > assets > js > plugins.js. you can see there is code that trigger ajax_filter_search. you will need to use it too.
$( document.body ).trigger( ‘ajax_filter_search’ );
jobplanet-plugin > lib > class-jeg-job.php
and on line 217, you can find build_job_seach_query. its query you need to alter.
And for your suggestion to use filter. Well it wont work, because search does not find any filters assigned to job.