A palindrome is a word, phrase, or sequence that reads the same forwards and backwards.
When enabled, it treats uppercase and lowercase letters as the same when checking for a palindrome, so "Racecar" is still recognized as one.
When enabled, it strips out spaces, commas, and other punctuation before checking, which lets phrases like "A man, a plan, a canal, Panama" be correctly recognized as a palindrome.
Yes, both "Ignore case" and "Ignore spaces & punctuation" are checked by default since most real-world palindrome phrases rely on ignoring both.
Yes, numeric sequences like "12321" are also checked correctly since digits are treated the same as letters for this comparison.