This is proprietary software. It doesn’t even meet the definition of Open Source.

This software and associated documentation files (the “Software”) may only be used in production, if you (and any entity that you represent) have agreed to, and are in compliance with, the Tabby Subscription Terms of Service, available at https://tabby.tabbyml.com/terms (the “Enterprise Terms”), or other agreement governing the use of the Software, as agreed by you and TabbyML, and otherwise have a valid Tabby Enterprise license for the correct number of user seats. Subject to the foregoing sentence, you are free to modify this Software and publish patches to the Software. You agree that TabbyML and/or its licensors (as applicable) retain all right, title and interest in and to all such modifications and/or patches, and all such modifications and/or patches may only be used, copied, modified, displayed, distributed, or otherwise exploited with a valid Tabby Enterprise license for the correct number of user seats. Notwithstanding the foregoing, you may copy and modify the Software for development and testing purposes, without requiring a subscription. You agree that Tabby and/or its licensors (as applicable) retain all right, title and interest in and to all such modifications. You are not granted any other rights beyond what is expressly stated herein. Subject to the foregoing, it is forbidden to copy, merge, publish, distribute, sublicense, and/or sell the Software.

https://github.com/TabbyML/tabby/blob/main/ee/LICENSE