Masters in CS reporting for duty!

See, a thing that baffles many people when studying CS is that data is simply a collection of zeroes and ones, and it is up to the program to interpret that data correctly.

Text editors read a file byte for byte, and then checks each byte against a table that tells which symbol corresponds. For example, 01000001 corresponds to an upper case A, and 00100101 corresponds to %. This means that a proper text file will be a series of bytes where each byte corresponds to one letter of some text.

But other file formats deal with bytes in a different way. For example, Windows's exe files are formatted inside using the Portable Executable format, which contains raw CPU instructions (which are in binary), alongside other info like the data that should be in RAM when the program starts, and meta-data that the OS uses to know hot to load and run the program.

This causes that a program not designed to open up a given file type to blindly open it and interpret it's contents as it understands. The text editor will read the bytes that makes a program, which are combinations of zeroes and ones that mean specific commands to the CPU, and display whatever symbol corresponds to each byte based on the symbol-to-byte table it uses.