Lorekeepers rejoice! Watchmen showrunner Damon Lindelof has confirmed the Peteypedia documents that were published after the release of each episode should be treated as canon to the universe of the HBO series.
To coincide with the premiere of Watchmen back in October, Peteypedia was launched on HBO's website. Similar in nature the supplementary material provided at the end of each issue of Alan Moore and Dave Gibbons' original Watchmen graphic novel, Peteypedia affords the HBO series some extra worldbuilding. Moreover, it provides additional context to things only mentioned in passing on-screen -- such as the publication of Rorschach's journal or the whereabouts of Nite Owl II.
In real life, Peteypedia was crafted by Watchmen's writers. In-universe, however, it is the brainchild of FBI agent and superhero historian Dale Petey. Even so, up until now, Peteypedia had questionable canonicity -- with many fans wondering if it should be taken into account when analyzing the show's story as a whole. Fortunately, man in charge has an answer, and it is a resounding "yes."
"Not to lean too heavily on the Peteypedia, but the Peteypedia is canon," Lindelof said in an interview with Collider. "And, a lot of the thinking that went into some of the creative decisions that we made on the show, we covered in Peteypedia."
In-universe, it seems Peteypedia was deleted shortly after the events of Watchmen's Season 1 finale -- with FBI Deputy Director Max Farragut announcing the firing of Agent Petey and blasting the historian's "self-indulgent memos." Luckily, the site is still up in real life for lore-oriented fans of the series to peruse. The final memo from Farragut even answered one of the finale's only unanswered questions, suggesting that Petey himself was most likely the mysterious vigilante known as "Lube Man."
Developed by Damon Lindelof, HBO's Watchmen stars Jeremy Irons, Regina King, Don Johnson, Tim Blake Nelson, Jean Smart, Louis Gossett Jr., Yahya Abdul-Mateen II, Tom Mison, James Wolk, Adelaide Clemens, Andrew Howard, Frances Fisher, Jacob Ming-Trent, Sara Vickers, Dylan Schombing, Lily Rose Smith and Adelynn Spoon.