Terms of use.

This page is a summary in plain language, not a substitute for the terms themselves and not legal advice.

What you may do

Install and use the app on your own computers, for as long as you like, without telling us who you are. The app itself has no account, no licence key and no activation of any kind, and nothing in it ever signs in. The account is a thing of this website alone: it exists so the contact form can tell a reader from a script, and it is the reason that form is asking for one. A download, an install and every setting the app changes need no account.
Use the portable build anywhere you personally use it. It writes nothing to Program Files and leaves no Start Menu entry, so nothing is left behind on a machine you do not own.
Take it off again whenever you want. The uninstaller removes the app, and Reset all app data clears the folder it kept in your own user profile.
Read the source of everything that ships beside it: the licences of the parts that are not ours are named below, and their sources are published by their own projects.

What you may not do

All rights are reserved. In particular:

You may not redistribute the app, sell it, or ship it inside another product, whether that product is free or paid.
You may not remove or alter the notices that name the app or the licences of the parts inside it.
You may not present it as your own work or as the work of anyone other than us.
Nothing here takes away the rights the third-party licences give you. Electron is MIT licensed, the IBM Plex Sans typeface this website uses is under the SIL Open Font Licence, and the optional temperature driver and its modules are under the GPLv2 and the LGPL-2.1. Those terms are theirs and they win over this summary where they apply to their own code.

What is promised

No performance improvement is promised. The app turns on settings Windows already has, and how much you notice depends on your PC and on what you run on it.
No fitness for a particular purpose is promised. This is a tool for changing Windows settings, and you are the one who decides which ones to change.
The app asks Windows for a restore point before a risky change and can roll its own changes back, but the backup is not a guarantee: a restore point can fail to be created, and the app says so when it does.
The installers are not code-signed yet, so Windows may warn the first time you run one. The overview page publishes the SHA-256 hash of each file this build produced, which is how you check that you got the file we published.

We do not guarantee a performance improvement. The app turns on settings Windows already has, and how much you notice depends on your PC and what you run on it.
The app's welcome screen

Installing and removing it

The installer shows this summary before it does anything, and installing is how you accept it. If you do not accept it, close the installer and nothing is changed.
The app asks for administrator rights once, at launch, because changing Windows settings needs them. Applying or reverting a setting never asks again after that.
The uninstaller removes the app from Program Files and takes its shortcuts with it. The folder of data in your own user profile is left alone unless you clear it yourself, so that a reinstall does not lose your settings.

What the app writes to disk is listed on the privacy and licence page, and every one of those files is named in the app's own source.

The parts of this that are missing

Two things are deliberately not on this page, and it is better to say so than to write something that is not true.

Neither the licence text the installer shows nor this page names a governing law or a jurisdiction. A clause naming one would have to be written by someone qualified to write it, and it is not in this repository.
This page is a summary written by the people who made the app. It describes what the software does; it is not advice, and it is not a substitute for the terms shipped with the installer, which are the document that applies.