Pebble is a smartwatch, once created by a no longer existing company as a kickstarter project in 2012. See wikipedia for more info; https://en.wikipedia.org/wiki/Pebble_(watch)
I do own a couple of these watches, and did create my own “watch face” for it. I still use the simpleweek-nl one, which displays the time, date, day, and week number.
The “strange” number in the top left corner is indicating the year divided by 13 (4 week periods), as was used in the past by the company I work at to indicate the billing period. The number behind the dot indicates the week count into this 4 week period.