Challenges

Does a white rook attack the black king along a rank or a file? Any piece standing between them blocks it.

Capture the text inside the FIRST <b>...</b> tag on the line — just the text, not the tags.

Capture everything before the FIRST equals sign: key=value=other gives key.

Match both the British and American spellings of "colour".

Extract every http and https URL from a block of text, and nothing else that looks like a scheme.

Extract every run of five or more lower-case letters.

Collapse every run of whitespace down to a single space.

Match strings containing three consecutive digits.