Problem adding release-key using instructions for Debian/Ubuntu

When trying to install syncthing using the http://apt.syncthing.net/ instructions I can’t find the release PGP key.

Visit the link you just provided in your web browser and you will find the instructions.

Edit:

So re-reading your post you know the instructions are on that page. The first line gives you the key

https://syncthing.net/release-key.txt

Thanks.