To reiterate: the expr object sources are now part of Pd's core src folder and named x_expr* with explicit permission of the original author. As far as I can tell, they now assume the same BSD license as that of Pd:

https://github.com/pure-data/pure-data/commit/82a5e455f859071698788c04df5d15c5b126c08a#diff-2515c59f4e79df785fc90cec7338c903

To be fair, the source file heard info was not changed until later and we are obviously still catching up with changing mentions of licensing in other places. Better would be to contact the authors of there aforementioned websites and ask them to update the license info. Then this whole email chain can be avoided the second time around.

On Sep 26, 2019, at 12:00 PM, pd-list-request@lists.iem.at wrote:

From: Alexandre Torres Porres <porres@gmail.com>
To: Nicolas Danet <nicolas.danet@free.fr>
Cc: Pd-List <pd-list@mail.iem.at>
Subject: Re: [PD] Expr objects are GPL or LGPL?
Message-ID:
<CAEAsFmjj_oupgcTJ9aV3Qop6v5FQiGQKm7rmP+K84C+b=KCcsg@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

well, miller now says it's not

and I actually also thought so, but then the note says differently

one way or another, we need to fix this and make it clearer in the pd
documentation

--------
Dan Wilcox
@danomatika
danomatika.com
robotcowboy.com