Re: documenting the backup manifest file format

+      The LSN at which replay must begin on the indicated timeline in order to
+      make use of this backup.  The LSN is stored in the format normally used
+      by <productname>PostgreSQL</productname>; that is, it is a string
+      consisting of two strings of hexademical characters, each with a length
+      of between 1 and 8, separated by a slash.

typo "hexademical"

Are these hex figures upper or lower case?  No leading zeroes?  This
would normally not matter, but the toplevel checksum will care.  Also, I
see no mention of prettification-chars such as newlines or indentation.
I suppose if I pass a manifest file through prettification (or Windows
newline conversion), the checksum may break.

As for Last-Modification, I think the spec should indicate the exact
format that's used, because it'll also be critical for checksumming.

Why is the top-level checksum only allowed to be SHA-256, if the files
can use up to SHA-512?  (Also, did we intentionally omit the dash in
hash names, so "SHA-256" to make it SHA256?  This will also be critical
for checksumming the manifest itself.)

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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