Working through the step by step review process; this is the first batch of issues I found

Typography

[x] Changes made by se typogrify on content.opf and summering-in-canadian-backwoods.xhtml should be accepted.
[x] Revert b22a2a13fac874d790906aae3b7e622bc3ebf003. Per Chicago 7.15, “the possessive of most singular nouns is formed by adding an apostrophe and an s” (without exception for words ending in s). Per 7.16, “the general rule extends to proper nouns, including names ending in s.” 7.21 notes specifically that the practice of omitting the possessive s on all words ending in s is not recommended by Chicago. SEMOS does not contain rules on possessives so we default to following the Chicago rules.
[x] se clean seems to be changing some whitespaces in the lint ignore file, which you should accept.

Spelling

[x] Running se modernize-spelling creates several valid changes. Pretty much all of them look good from me apart from the ones that are trying to change may-day to mayday in an id.
[x] I see several valid changes coming from se semanticate. I want to point out in particular that in some lines of sambo-and-snitch.xhtml you have a valid eoc class being added while bogus Roman numeral semantics are also being added. You’ll still want to add the eoc though the Roman numeral semantics should be discarded.
[x] The one instance of “a-quiver” should be modernized to “aquiver”