Heroku: Slug size is way bigger than local because of .apt file?

  flask, heroku, python, web-applications

I deployed my first python + flask webapp a while ago using heroku and always got the warning
Your slug size (365MB) exceeds our soft limit (300MB). Didnt mind too much until now when I looked up what exactly takes up how much space. Running bash to inspect the slug I get the following:

1.1G    /app
649MB   /app/.heroku
364M    /app/.apt
28M     /app/Lib
12M     /app/.chromedriver
2.0M    /app/Scripts
32K     /app/.procfile.d
20K     /app/__pycache__
16K     /app/main.py
4.0K    /app/hashtable.py
4.0K    /app/Procfile
4.0K    /app/requirements.txt
4.0K    /app/.locales

This doesnt look exactly like what I have locally. I suppose the .heroku folder was added by heroku but the .apt too since that one is not on my local machine. If I look into it with cd and ls it very much looks like things that heroku needs so Im a bit careful to delete it

Im just confused because I never saw .apt on other projects and I feel like Im doing something wrong when all of my files are around 33MB and I have no idea where the other 330MB come from. Cant imagine that heroku puts 300MB of must needed files into the slug to run the web application

Does anyone have an explanation?
The buildpacks I use are:


Source: Python Questions