Spotted on gallium in /srv/org/wikimedia/doc there is a bunch of directories such as:
```
$ find /srv/org/wikimedia/doc -maxdepth 3 -wholename '*wmf/*' -type d
./Flow/wmf/1.26wmf15
./Flow/wmf/1.26wmf12
./Flow/wmf/1.26wmf19
./Flow/wmf/1.26wmf16
./Flow/wmf/1.26wmf22
./Flow/wmf/1.27.0-wmf.3
./Flow/wmf/1.26wmf24
./Flow/wmf/1.26wmf17
./Flow/wmf/1.27.0-wmf.1
./Flow/wmf/1.26wmf10
./Flow/wmf/1.26wmf18
./Flow/wmf/1.26wmf9
./Flow/wmf/1.27.0-wmf.6
./Flow/wmf/1.26wmf11
./Flow/wmf/1.27.0-wmf.2
./Flow/wmf/1.26wmf21
./Flow/wmf/1.26wmf20
./Flow/wmf/1.26wmf13
./Flow/wmf/1.27.0-wmf.4
./Flow/wmf/1.27.0-wmf.5
./MobileFrontend/wmf/1.26wmf16
./MobileFrontend/wmf/1.26wmf22
./MobileFrontend/wmf/1.27.0-wmf.3
./MobileFrontend/wmf/1.26wmf24
./MobileFrontend/wmf/1.27.0-wmf.1
./MobileFrontend/wmf/1.26wmf23
./MobileFrontend/wmf/1.27.0-wmf.2
./MobileFrontend/wmf/1.26wmf21
./MobileFrontend/wmf/1.26wmf20
./MobileFrontend/wmf/1.27.0-wmf.4
$
```
Most probably the job is lacking a proper branch: filter in Zuul configuration.