The year 2020 has been brought to you by the letters W, T, & F.

The characters are Bert & Ernie from Sesame Street. It's a children's show with live people, puppets, and animation to engage kids and introduce them to early childhood educations, ie numbers & counting, letters, shapes, colours, etc.

Sesame Street episodes are always bought to you by a letter of the alphabet to teach kids letter familiarity - 2020's letters are What The Fuck acronym

@scurry So what is an Ernie & a Bert to do with wtf?

@FrayedBear Each episode used to focus on a few numbers and/or letters. Part of the shtick was to reitterate the numbers/letter by saying the show was brought to you by these letters/numbers like they were advertisers...
Such as Brought to you by Valvoline and Coca-Cola.
But instead, they would say brought to you by the letter X and number 7... Or whatever. (in this case, the joke is W, T, & F)
Often the characters in the show would say the line.
Note: the show often touched on many topics like a new baby, moving, racisim, disabilities...

@scurry Thanks for the explanation.

@FrayedBear No worries. Cultural references can be confusing if they aren't familiar.

@scurry if one has never stayed home with kids ( or been too hung over to change the channel ) the Sesame Street reference would be foreign.

@wolf041 lol it's nearly 40 years since children's programmes were on TV here. I've got better things to remember - like my name & the day of the week.