Is the grid viewer accessible to a user program?

[BruceH]

If you press shift+MEM, scroll down to Matrices, press ENTER, then choose one of the M0-9 matrices and press Enter again a spreadsheet-like viewer environment is entered.

Is there any way to call/invoke/use that "grid viewer" from a user program to display my own values?

And by "my own values" I mean custom column headings and menu line (if possible) as well as content.