What a mess.
URL is still advanced-custom-fields, but then named Secure Custom Fields. Translations and source repo still map to the old name. It definitely is a takeover, not a "fork" in the classic, established sense.
The problem with the takeover is, of course, that the original publisher still develops, publishes, and sells their original plugin. Their official website now serves their own version with their own update source.
So you kinda don't but also have to rename it to avoid confusion.
I think a rename to something different is wrong and confusing though. It should add a disclosing addition, like "(Taken Over)" or "Adjusted" or "WPorg edition".
A supposed, partial rename is confusing. No information in the README is confusing, intransparent, and disingenuous. No clarity in the release notes is confusing.
Simply freeing previously and still sold pro features, without disclosing that fact, is very questionable. Not fair to the developers and certainly not transparent to the community.
Clearing the changelog and release log documentation, removing previously available information, is questionable as well.
I see in the readme.txt file that the plugin is licensed under GPL.
So the changes are permissible. And being able to do so is certainly a strength of the FOSS license.
My biggest issue is that they remove information, and rename without indication. It should be transparent and, within context and concerns, fair. Not like this.
Looking at the commit log:
6 days ago, 6.3.6.1 was tagged with
Security - ACF defined Post Type and Taxonomy metabox callbacks no longer have access to $_POST data. (Thanks to the Automattic Security Team for the disclosure)
14 hours ago, 6.3.6.2 and rename
- Security - Harden fix in 6.3.6.1 to cover $_REQUEST as well.
- Fork - Change name of plugin to Secure Custom Fields.
It also removes is-pro and pro-license-active checks, but fails to disclose so in the release notes.
Effectively, it frees pro functionalities.
It also removes all previous change log and release information.