Mastodon said it sent a formal letter to 'Truth Social' after media reports found the site was using Mastodon's codebase while not respecting a part of its software license.
On October 21, 2021, the Software Freedom Conservancy group stated they suspected Truth Social had violated Mastodon’s AGPLv3 license by not offering its source code to all users. The Mastodon developers then formally requested that Truth Social comply with the terms of the software license, with Truth Social publishing its source code as a ZIP file on the website on November 12, 2021. On February 22, 2022, the source code download was moved to the website’s legal section. A mirror of the source code is available at GitHub, where it was uploaded by uninvolved individuals.
They released the source code.
From Wikipedia:
https://en.wikipedia.org/wiki/Truth_Social#Software
https://github.com/justjosias/truth-social