Hi Adam,
thank you for the question, the list of GenMT didn't change, however as every year blindset contains also test suites, this year we allowed test-suite participants to include also unsupported languages because multilingual systems are taking over bilingual systems.
You can choose not to translate these languages, however, we'd encourage everyone who builds multilingual systems to translate them, unsupported languages won't affect system ranking and in the model card poll you can list the supported languages which same as last year we will highlight in the findings.
One additional comment, while it may look like additional languages (such as mni_Beng) are much larger than the GenMT languages, it is because those are sentence level, while GeneralMT data are document level. In reality, all test-suites together are just a bit larger than whole GenMT blindset in terms of word count.
Have a lovely day,
Kocmi