Thin search results because the file is genuinely boring until the one day it is not. SRS is the Send Receive Settings file, storing your send receive groups: which accounts sync, which folders each group covers, the scheduling intervals and the offline behaviour, everything configured under the Send / Receive Groups dialog lives in that file, one per Outlook profile as you spotted.

Size wise it is irrelevant to your roaming profile hunt, SRS files run to kilobytes. Their real significance is the misbehaviour they cause when corrupted: send receive errors with no better explanation, most classically the 0x8004010F family, groups that ignore their schedule and sync settings that revert or refuse to save. When those symptoms resist the ordinary fixes, the SRS is the unglamorous suspect.

And that is where deletability becomes the useful property: fully safe, because Outlook rebuilds a default SRS on the next start. Close Outlook, rename the profile's .srs in %appdata%\Microsoft\Outlook, keeping the rename rather than deleting out of ordinary caution, then start Outlook to a fresh default send receive configuration. Mail and account settings are untouched, those live elsewhere entirely.

The single cost: customized send receive groups reset to defaults, so anyone who built elaborate group configurations rebuilds them afterwards. Most people run the defaults and lose nothing at all, making the SRS rename one of the cheapest troubleshooting moves Outlook offers.