WTFPL should be accepted as a GPL-compatible license

[nilovelez]

The Plugin Check Plugin currently reports an error when a plugin declares the WTFPL (Do What The F*ck You Want To Public License) as its license, stating that the plugin must use a GPLv2-compatible license and pointing to the following documentation:

https://developer.wordpress.org/plugins/wordpress-org/common-issues/#no-gpl-compatible-license-declared

That page states:

“Remember that all code, data, and images — anything stored in the plugin directory hosted on WordPress.org — must comply with the GPL or a GPL-Compatible license. Included third-party libraries, code, images, or otherwise, must be also compatible.

For a specific list of compatible licenses, please read the GPL-Compatible license list on gnu.org.”

The linked GNU license list explicitly classifies the WTFPL as GPL-compatible:

https://www.gnu.org/licenses/license-list.html#GPLCompatibleLicenses

The entry for the WTFPL states:

“This is a lax permissive non-copyleft free software license, compatible with the GNU GPL.”

Given that the official GNU license list explicitly marks the WTFPL as GPL-compatible, the Plugin Check Plugin should accept WTFPL as a valid GPL-compatible license and should not flag it as an error.

[davidperezgar]

I see that it is actually being used by 1,404 plugins in the directory. So it's widely used.