Tapestry (4 and 5) has traditionally honored all the white space in a template. This is for a few specific cases, such as text inside a <pre> element (who uses those?).
This results in output documents that, due to the extra whitespace that often surrounds Tapestry components, contain large amounts of whitespace.
In most cases, interior white space (whitespace between text characters) can be reduced to a single space, and white space just after a tag or just before a tag can be eliminated entirely.
The Tapestry template parser should honor the xml:space attribute and use it to determine what template whitespace is relevant, and what whitespace may be minimized or eliminated.