Invisible Dots

When using Microsoft Word, I like to reveal the invisibles, you know, see the behind-the-scenes formatting on the page. I recently discovered some mysterious items that I cannot figure out.

When  working on a table, I found these invisible dots in the table cells.

Do you have any idea what they are for? They are not placeholders for text, as they are still there even when text is entered into the cell.

April 2021
M T W T F S S
 1234
567891011
12131415161718
19202122232425
2627282930