HI jona, welcome to osm!.
with this tool:
https://osmcha.org/changesets/134924428/
you can analyse changes made in a changeset. (just edit the changeset# in the address)
oneway=no is usually not tagged.
see
https://wiki.openstreetmap.org/wiki/Key:oneway
"..only in order to avoid mapping errors in areas where e.g. oneway streets are common, or to override defaults..."

Cheers
Carsten