There are absolutely no "designed-for-URX tags" that we have documented. All of the meta/link tags that are documented are usable by Twitter, Facebook, Google, etc. It might not be entirely clear in our documentation unfortunately, but the "omnilink standard tags" are actually just an extension of Google's app-indexing tags, and are fully compatible with their initiative.
There are absolutely no "designed-for-URX tags" that we have documented. All of the meta/link tags that are documented are usable by Twitter, Facebook, Google, etc. It might not be entirely clear in our documentation unfortunately, but the "omnilink standard tags" are actually just an extension of Google's app-indexing tags, and are fully compatible with their initiative.
[full disclosure, I'm an engineer at URX]