I believe the OP is referring to one of the Tartans, not just rainbow inserts.

This is The Tartan of Pride and is just one.

SRT # 5684 with this description

Designed by Patrick McVey Gillion and Goran Broberg of Scottish House in Stockholm. "The tartan is made to unite all people that believe in Love and Respect. The colours are from the rainbow and symbolise that we are all different but beautiful". Originally woven by Marton Mills.

Mr Goran Broberg, Broberg Sodermannagatan 41 C, Stockholm, Stockholm, Sweden, 11640
lgbroberg@gmail.com