The most common and most likely answer to this crossword clue is the 10 letter word PONTIFICAL
I've seen this crossword clue in The Guardian
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More clues leading to the result PONTIFICAL
Buddy explains!

The straight part
We know that "for the pope" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case for the pope = pontifical.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PONTIFICAL mean?
PONTIFICAL noun- A book containing the offices, or formulas, used by a pontiff.
- Of or pertaining to a pontiff.
- Pompous, dignified or dogmatic.
- Splendid; magnificent.
- Of or pertaining to the pontifices of Ancient Rome.
- Of or relating to the building of bridges.