For work or for personal?

For work, it's my bespoke spreadsheet that automatically calculates when and how much I need to have on hand for any particular item. Our system is technically able to do this, but no one has ever turned it on, so I created one myself in order to get my inventory under control.

At home, it's probably the blender file of my current project for X-Plane that represents roughly a year and a half of my life so far. I have backups in multiple places of course.

It was my Bitcoin wallet before I sold. Now it's probably my password vault.

mullvad.exe

Spreadsheet template for paying bills.

My collection of .EXE files out of which the most important is the one i use daily.

My most important file is an insanely customized, self-compiled binary on Gentoo, embedded with multiple layers of encrypted payloads—using a hybrid of AES-256 and RSA, stored in a hidden LUKS partition on a remote server. The entire setup is wrapped in a fortress of security-hardened CFLAGS, with each layer only accessible via a complex, time-sensitive keystroke sequence using a YubiKey. The system is so finely tuned that it only runs on a specific kernel version optimized for speed and stealth, pivoting through an ever-shifting network of proxy chains. If anyone tries to tamper with it, the dead man's switch wipes everything in an instant. Good luck finding it OP.