Back in the bad old days, Mats, they often fitted an "interceptor" just after a manhole, before the sewer connection. This was effectively a trap (or U-bend). If it bunged up, there was a removable plug just above it. This was taken off so that "direct" rodding could clear the blockage.
I said "bad old days" because these things were forever getting blocked.......... eventually, in most cases, the plug was thrown away, effectively bypassing the interceptor.
So much for the history lesson ..................... for as long as I can remember, the connection to the sewer has been "straight through".