Tinderbox regular expressions ('regex') recognise a number of patterns containing the backslash character. Some common examples are:
\s matches any whitespace character
\S matches anything EXCEPT a whitespace character
\w matches a word character, such as a letter
\W matches any non-word character, such as punctuation
Otherwise Tinderbox uses normal regular expression escaping (i.e. to double-escaped backslashes). For example:
"this\sthat"
recognises
"this&[tab char]&that"
as well as
"this that"