system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it when I open a executable/file in notepad it mostly looks like random glyphs?
gpt
All computer files are made up of bytes. A byte is 8 binary digits, and this can hold a number between 0 and 255.

Some of these numbers represent regular everyday characters - for example, 65 is the character "A". Notepad assumes, when you load a file, that the file contains printable characters, and tries to display them to you.

(ELI12 note: it also checks to see if the file contains Unicode, where it groups two bytes together to make a single character. Not relevant to the question, but included for completeness.)

When you load an executable file into Notepad, some of the bytes in the file will, by chance, be regular printable characters. But many of them won't. Even though they aren't regular characters, they still get displayed on the screen. Each code between 0 and 255 has a meaning when it comes to displaying it - but for many of those codes, the meaning is simply a weird-looking shape, and that's what you see.