What Paul Eggert has (100421 MMD) is a British player piano roll and
"Imperial" is the company's brand name.  "Linenized" is correct for the
usually green linen roll leader.  I think they are neat.  Also the end
tab usually has a pin sticking out, which holds the length of string
provided for wrapping around the roll, another nifty idea that this
company had.

The "Accentist" on the label refers to the snakebite "theme"
perforations on the sides of the roll.

"Compass" and "Full compass" refers to the number of notes your player
piano or pianola (for the other countries; "player piano" for us in the
USA) has.  A "full compass" roll of course refers to an 88-note piano
roll.

Hope this answers your questions.

Larry Norman 
  From beautiful Smith Mountain Lake where we just had the Bass
  Tournament, with a $100,000 prize for the best catch.