The side path here is not a publicly accessible path and shouldn't exist on the map. it appears to be the entrance to somebodies back yard. the adjoining main path connected to romilly road and harbour road is an alleyway with many entrances to other people's yards and is publicly accessible.

via StreetComplete 56.0

Attached photo(s):
https://westnordost.de/p/192929.jpg
https://westnordost.de/p/192930.jpg