Just as you did with Studio

see docs: https://docs.intersystems.com/ens201813/csp/documatic/%25CSP.Documatic.cls?LIBRARY=%25SYS&CLASSNAME=%25CSP.Response#ContentLength
• property ContentLength as %String;

Sets the Content-Length header. Since the HTTP headers are sent after the OnPreHTTP() method is complete, setting it after this has no effect.

As a first step I would search Journals to find the Globals affected
if they are not in IRISTEMP/CACHETEMP or PPG of if Journal is switched off.

In order to separate routine calls (abc^myroutine) from real ^globals

Though journal just shows Process Ids, no routine names.