That only shows the % discount of the games, not the bundle; since there are multiple discounted games, Steam adds up the discount of the games in total and gets an average.

273/11 = 24.80 rounded to 25%. It's a bit strange that they show it like that since it doesn't matter at all since it takes the value of the products and only applies the discount of the bundle.

valve changed at some point how they display bundle discounts. I guess to reduce confusion for the customer, but i am not sure this way is an improvement. To answer your question, the green 27% discount shown to you is the value you save when compared to the (already reduced) bundle price because of the individual game discounts.

-26% for me and I own none of them

Not all people wait for 80+% discount on Steam or buy games almost exclusively in bundles.

this is called a bundle just because they come together

That's the definition of the word, yeah

Most of these games are not published by them, could be featured in future bundles nontheless though.But that's the case for alot of games, especially indie titles.

available for 96 hours

I mean yeah for $20 this is a no brainer if you don't already have everything except the indie games they added in there for the bait. The variety of the 2k pack is huge comparing to the one OP shared.

Technically it's not a bundle, it's a package (you always pay full $20 price regardless if you have some of the games already)

someone make one for it

Please or something, or just do it yourself, instead of ordering people around?

You save 26% on top of the 65% bundle discount resulting in a total discount of approx. 75%.
Compare the final price to the 240 USD advertised total worth, or just calculate the final discount yourself: 1-(1-0.65)*(1-0.26)=0.741 so just short of 75%

same, not interested