Upstream released a new 0.2.1 version, with a license version update:

https://github.com/pali/libopenaptx/releases/tag/0.2.1

The changelog has:
https://github.com/pali/libopenaptx/commit/811bc18586d634042618d633727ac0281d4170b8
* https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2235
* https://gitlab.freedesktop.org/pipewire/pipewire/-/merge_requests/664
* https://bugs.gentoo.org/785634

Most of the difference between 0.2.0 and 0.2.1 is this license change; see
https://github.com/pali/libopenaptx/compare/0.2.0...0.2.1

In the rest of the changes, there's also a patch I proposed, which is already
in the 0.2.0-* Debian packaging.

So. Notwithstanding the license change (which, at first glance, don't seem
acceptable for Debian), the rest of the updates don't justify upgrading this
package to 0.2.1, so I'm (as maintainer) tagging this as +wontfix.

Just to prevents others from spending more time digging into this:

libfreeaptx, which is a fork of libopenaptx 0.2.0, is available in
Debian since bookworm.

The only reverse dependency of libopenaptx at the time of writing is
baresip.

AIUI, there's currently no functional difference between both libraries.