CSm1n

Notepad was just a wrapper around some default win32 controls. Judging alone by exe size is not right, although probably a “statically linked” notepad would still be smaller than emacs

No, you can't. When you use 7-era toolchain (e.g. VS 2012) it sets the minimum client version in PE header to Vista, not XP much less 2k.

Yes, you can! There are even multiple Windows 10 era toolchains that officially support XP. VS 2017 was the last release that could build XP binaries.

It is a flag that says whether the loader data is initialized or not.

The layout of PEB_LDR_DATA “leaked” long time ago in public PDBs.

More context: It has nothing to do with debugging. However, if you attach to the process early enough, you might see the flag as 0 and eventually it would switch to 1. That is probably what threw him off.

The repositories shown on the first page of GitHub search are not actual exploits. They all expect to be run through an admin powershell/command line. Under normal conditions (default user and UAC on) you will get a warning before the script is able to gain administrative access. Try to run them again under a normal user and they won't be able to disable/bypass Defender.

It's the same as sudo'ing an unknown script you received in an email. At that point you're begging to be pwned.