The local pack is Google's map block.
For searches like "plumber near me", google.co.uk often shows three businesses in a map box at the top, above the usual list of websites. That box is the local pack, sometimes called the map 3-pack. It is not the email we send you.
Your daily digest says whether your business was in that box, and roughly which of the three slots, as a UK phone saw google.co.uk that night. The numbered results underneath (your site #3, a competitor #7) are the normal Google list. The map box is separate. You can be in one, both, or neither.