That always depends. ESPHome only compiles features that you actively add to your device config (yaml) 
If you search for a particular function (ota, web server, etc.) maybe just tell us so people can help you what are you looking for 
Describe the goal, not the problem
It’s all too easy to fall into the trap of the XY problem . If you describe your goal first, then others can understand what you’re trying to achieve.