There is a a COVID-19 Addendum and a Remote Duel Addendum
The COVID-19 addendum discusses how to adapt physical tournaments to comply with safety practices
"Some tournament actions, such as shuffling and reporting Match results, can be handled differently as a result. The addendum explains how to address these concerns."
There's also the Remote Duel Addendum, which clarifies some competitive rules
The Remote Duel document "covers similar information as the Best Practice Guide, with a focus on policy-specific instructions."
If you are a competitive player, check out the official announcement to read the documents and the details on them!