COPYING.README

The following applies to tinc:

> This program is released under the GPL with the additional exemption that
> compiling, linking, and/or using OpenSSL is allowed.  You may provide binary
> packages linked to the OpenSSL libraries, provided that all other requirements
> of the GPL are met.

The following applies to the LZO library:

> Hereby I grant a special exception to the tinc VPN project
> (https://www.tinc-vpn.org/) to link the LZO library with the OpenSSL library
> (https://openssl.org).
>
> Markus F.X.J. Oberhumer

When tinc is compiled with the --enable-tunemu option, the resulting binary
falls under the GPL version 3 or later.