Add note on dabbrev case folding

gists.org

@@ -638,6 +638,42 @@ Based on an answer at the [[https://emacs.stackexchange.com/a/77480/34645][Emacs
   (add-hook 'find-file-hook #'my/file-setup)
 #+end_src
 
+* Dabbrev case :emacs:
+
+#+begin_src org
+  ,* dabbrev-case-replace
+    - nil : Replace expansion's case pattern.
+    - *case-replace*: Preserve if =case-replace= is nil.
+    - else : Modify by applying abbreviation's case pattern.
+
+  ,** case-replace
+
+  - nil: Don't preserve case in replacements.
+  - *t*: Preserve case in replacements.
+
+  ,* dabbrev-case-distinction
+
+  - nil: Treat expansions the same if they differ in case.
+  - *case-replace*: Distinguish if =case-replace= is nil.
+  - else: Treat them the same.
+
+  ,* dabbrev-case-fold-search
+
+  - nil: Case is significant.
+  - *case-fold-search*: Significant if =case-fold-search= is nil.
+  - else: Case is not significant.
+
+  ,** case-fold-search
+
+  - nil: Searches and matches don't ignore case.
+  - *t*: Searches and matches should ignore case.
+
+  ,* dabbrev-upcase-means-case-search
+
+  - *nil*: Case fold search when searching for possible expansions.
+  - else: Non-nil means case sensitive search.
+#+end_src
+
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