diff --git a/hledger-lib/Hledger/Read/RulesReader.hs b/hledger-lib/Hledger/Read/RulesReader.hs
index 09329a879..f457ff563 100644
--- a/hledger-lib/Hledger/Read/RulesReader.hs
+++ b/hledger-lib/Hledger/Read/RulesReader.hs
@@ -124,17 +124,17 @@ getDownloadDir = do
 -- Instead, a data file (or data-generating command) is usually specified by the @source@ rule.
 -- If there's no source rule, the data file is assumed to be named like the rules file without .rules, in the same directory.
 --
--- The source rule supports ~ for home directory.
--- If the argument is a bare filename, its directory is assumed to be ~/Downloads.
--- If is a relative file path, it is assumed to be relative to the rules file's directory.
+-- The source rule supports ~ for home directory: @source ~/Downloads/foo.csv@.
+-- If the argument is a bare filename, its directory is assumed to be ~/Downloads: @source foo.csv@.
+-- Otherwise if it is a relative path, it is assumed to be relative to the rules file's directory: @source new/foo.csv@.
 --
--- The source rule can specify a glob pattern.
--- If the glob pattern matches multiple files, the newest (last modified) file is used (see also below).
+-- The source rule can specify a glob pattern: @source foo*.csv@.
+-- If the glob pattern matches multiple files, the newest (last modified) file is used (with one exception, described below).
 --
--- The source rule can specify a data-cleaning command, after the file pattern and a | separator.
+-- The source rule can specify a data-cleaning command, after a @|@ separator: @source foo*.csv | sed -e 's/USD/$/g'@.
 -- This command is executed by the user's default shell, receives the data file's content on stdin,
--- and should output data suitable for hledger to convert with CSV rules.
--- A # character can be used to comment out the data-cleaning command.
+-- and should output CSV data suitable for hledger's conversion rules.
+-- A # character can be used to comment out the data-cleaning command: @source foo*.csv  # | ...@.
 --
 -- When using the source rule, if the archive rule is also present, some behaviours change:
 --
diff --git a/hledger/hledger.m4.md b/hledger/hledger.m4.md
index cb21b60fc..26c5ae576 100644
--- a/hledger/hledger.m4.md
+++ b/hledger/hledger.m4.md
@@ -3299,7 +3299,9 @@ See also ["Working with CSV > Reading files specified by rule"](#reading-files-s
 After `source`'s file pattern, you can write `|` (pipe) and a data cleaning command.
 If hledger's CSV rules aren't enough, you can pre-process the downloaded data here with a shell command or script, to make it more suitable for conversion.
 The command will be executed by your default shell, will receive the data file's content as standard input,
-and should output zero or more lines of character-separated-values, ready for conversion by hledger's CSV rules.
+and should output zero or more lines of character-separated-values, ready for conversion by the CSV rules.
+
+*Added in 1.50; experimental.*
 
 ## `archive`
 
@@ -3314,6 +3316,8 @@ regenerating entries with improved rules,
 checking for variations in your bank's CSV,
 etc.
 
+*Added in 1.50; experimental.*
+
 ## `encoding`
 
 ```rules