The extra notes are just wrong
unconjugated bilirubin is the precursor for urobilinogen according to amboss and numerous papers
https://next.amboss.com/us/search?q=bilirubin+metabolism&v=overview&m=KKaUhl
"Conjugated bilirubin delivered to the gut from the biliary system is deconjugated by β-glucuronidase and subsequently reduced by intestinal microbiota in the intestinal lumen to bilirubin metabolic compounds including urobilinogen" - PMID: 29409713 with 211 citations
"When bilirubin diglucuronide is deconjugated by human or bacterial beta-glucuronidases into unconjugated bilirubin, it can be readily reabsorbed into the enterohepatic circulation or further metabolized via reduction reactions by gut microorganisms into the more excretable metabolites urobilinogen and stercobilinogen" - PMID: 38172624 published in Nature Microbiology 2024
Source: AMBOSS - https://next.amboss.com/us/search?q=bilirubin+metabolism&v=overview&m=KKaUhl
Comments; card as stated is true if incomplete. Would need to see evidence that knowing the CB gets reconverted to UCB is necessary