If I were writing a commentary on Hebrews, here would be my introduction:
1. We don't know who wrote Hebrews.
2. We don't know who Hebrews was written to.
3. We don't know when Hebrews was written.
So, let's get into the text and find out what Hebrews is about.
FYI - This is meant to be something of a joke for those who have ever read the introductory material in Hebrews commentaries. They go on for pages and pages of speculation and then make the conclusions I've listed above.