This is similar to the surrounding whitespace test but for whitespace inside of a tag as opposed to before/after the first element of the template.
Through experimentation I have determined that DustJS:
- Ignores newlines entirely (probably why there is a special character for newlines)
 - Ignores spaces on empty lines
 - Ignore tabs on empty lines
 - Honors interior tabs
 - Honors interior spaces
 - Honors trailing spaces on opening, body, and closing tags
 - Honors trailing spaces on tagless lines with content
 - Honors trailing tabs on opening, body, and closing tags
 - Honors trailing tabs on tagless lines with content
 - Ignores leading spaces on opening, body, and closing tags
 - Ignores leading spaces on tagless lines with content
 - Ignores leading tabs on opening, body, and closing tags
 - Ignores leading tabs on tagless lines with content
 
Definitions
Interior: Surounnded by tags on the same line:
{foo}this is interior{/foo}
Trailing: On a line with a tag but no tag following it on that line:
{stuff}
{name}this is trailing
{other stuff}
Leading: On a line with a tag but no tag preceding it on that line:
{stuff}
this is leading{name}
{other stuff}