dev-python/python-slugify-1.2.6 needs to be stabilized, so that app-i18n/transifex-client-0.13.9 can be stabilized, which is required for Python 3.{7,8} support. Reproducible: Always
For the first stabilisation, you have to specify which arches you want. I assume it's amd64 and x86 given those are the only valid options here. In future, you can then use *. Then just add the CC-ARCHES keyword.
amd64 stable
x86 stable. Closing.