Sorry for the late reply!
Thanks for the message, the allowed locales for translation are in the translator.xml Just go ahead and add the correct locales for your languages I am guessing that will be bg_BG and ru_RU.
Please also create a story on Jira to contribute your pull requests to. https://jira.project-hop.org
We would love to have more slavic language support! If you have any questions feel free to ask here or on https://chat.project-hop.org
Best regards, Hans