This is the "do not cross" line. For the 9892 audio amp, the datasheet typically lists:
If Pin 5 stays at Vcc (e.g., 24V or 5V) constantly: my 9892 datasheet
Based on my analysis of component databases (DigiKey, Mouser, Octopart), the “9892” marking appears most frequently in three categories: This is the "do not cross" line