_ijt comes from IntellijIdea Token , in the source TOKEN_PARAM_NAME this is TOKEN_PARAM_NAME :
// we must check referrer - if html cached, browser will send request without query val token = headers().get(TOKEN_HEADER_NAME) ?: QueryStringDecoder(uri()).parameters().get(TOKEN_PARAM_NAME)?.firstOrNull() ?: referrer?.let { QueryStringDecoder(it).parameters().get(TOKEN_PARAM_NAME)?.firstOrNull() }
Appeared to protect the embedded server from CSRF .
PS Past wrong version:
Random is added so that the browser does not cache the content, otherwise some browsers may show a cached version of the already modified file, and you will send complaints to the PHPStorm developers.
This is not a "postscript", but a URL parameter.