Rsync does not exclude files or folders with "[" or "]" in file/folder name

The manual page says

--exclude-from=FILE     read exclude patterns from FILE

Note the word patterns. The exclude list does not consist of mere file names, but patterns. Try backslashes:

test \[folder4\]

From the rsync man page, "INCLUDE/EXCLUDE PATTERN RULES" section:

• a '[' introduces a character class, such as [a-z] or [[:alpha:]].
• in a wildcard pattern, a backslash can be used to escape a wildcard character, but it is matched literally when no wildcards are present. This means that there is an extra level of backslash removal when a pattern contains wildcard characters compared to a pattern that has none. e.g. if you add a wildcard to "foo\bar" (which matches the backslash) you would need to use "foo\\bar*" to avoid the "\b" becoming just "b".

This means that [file4] will be treated as a pattern that matches any of the single characters "f", "i", "l", "e", or "4". To get the square-brackets to be treated literally, you need to escape them, like: test \[file4\].txt.