I'm new to gardening. I bought some tomato plants and they're doing
well. Each was marked at a certain number of days such as 'Early Girl 80
Days'. What is 80 days? Does it mean the number of days from seed to
edible fruits or something else?

I saw no explanation of 'days' anywhere in the garden center where I
bought the plants. As a comment, I bought these plants which were about
as tall as my thumb in early June. Today they are up to my chin - or
about 165 cm. They are intermingled because I only planted them maybe 30
cm apart. I figure they are ok that close. Should I trim off the
branches which intrude on their neighbors?