Markers describe risk, not a guaranteed reward
Update 0.4.0.84 says threat markers now show enemy-spawn type, size through color, and possible loot categories including Active Matter, weapons and equipment. Earlier notes also moved detailed threat information into tooltips.
Practical use
Open the current tooltip before committing to a detour. Use it to compare risk against your available ammunition, medical supplies and time to extract.
Version note
This independently written guide summarizes current official update information. Check the live game client and official notes before making a high-risk decision, because live-service rules can change.
Independent guide based on supplied research and current official information.