Mosaic is made by a solo developer, not a company. There's no corporate entity behind it yet, just "the developer," reachable at the same email address used everywhere else on this site. These terms will get more formal if and when that changes.
The short, honest version.
A verified email is required to receive a working license key, issued once you've subscribed. The key is signed, and the plugin verifies it on your own machine. Its one network call renews that key: it sends the key to mosaicplugin.com and gets a fresh one back while your plan is active. Nothing about your design files or your usage is sent anywhere. Each key carries its own expiry date and stops working once that date passes. This is not tamper-proof DRM and is not meant to be.
Mosaic is a single $39.00 payment, processed by Paddle, with nothing to renew and nothing to cancel. If you want out, contact the developer within 7 days of your payment for a full refund; after 7 days, payments are final. If you have a billing question, contact the developer and it'll get sorted out directly.
The capability report the plugin generates for each import (the one marking every element native, approximated, rasterized, or unrepresentable, with a reason) is the authoritative answer to what Mosaic can and can't do for your specific design file. See the limits section above for the general shape of that.
These terms may be updated as the plugin and its pricing mature. If that happens, it'll be posted here with a new date, not applied retroactively to a subscription you already paid for that period.
Questions about any of this go through the Mosaic Discord, read directly by the maker of Mosaic.