Possible Clues:

• Message starter, for short
• Post-it initialism
• "Just so you know," in a text
• “This might be interesting,” for short
• Letters before a heads-up
• 'Just so ya know . . .'
• "Just a heads-up," on a memo
• Letters meaning "No action needed, but ..."
• Message opener
• 'Just so you know . . .'