The undesired functionality
In Chrome 95 there was introduced new functionality where the user can hover and click on the unit part of a css value to hotswap the unit.
The feature is part of a package solution that has been labeled "Length Authoring Tools" in the release notes, and can be seen in action and described in detail in the release notes on the official blog.

How can this feature be disabled?

Issue 1:

If a css-line in the inspector says padding: 0 10px; then the user can click the px-part of the line and open a selector that let's the user swap px to other units such as rem,vmax or in.
Clicking this part of the value no longer lets the user edit the entire value quickly. Most users already know what unit they desire to use beforehand, so they do not need to be helped to accidentally select pt or vw when working exclusively with px everywhere else.

Issue 2:

When selecting and copying properties from the inspector there is now inserted whitespaces/new lines between the value and the unit since the unit portion seems to be considered a separate element. This makes prototyping in the devtools and copy/pasting to external documents very tedious and broken.

CodePudding user response：

So here is the correct answer for now:

You can't.

(Though fixes are coming!)

It is not possible to toggle this feature in the current live stable release ( Chrome 95.0.4638.69 ).

Fixes have been added to Chromium ( [1], [2], [3] ) that are slowly making their way to the stable release of Chrome.

But help is on it's way..

Chrome 96 is scheduled to be released on November 16 2021 (source) and will at least contain a revert to free text editing of css properties (source). Hopefully version 96 will adress the issue completely, but if it doesn't then the next major release is scheduled for January 4 2021 (If this issue is unresolved by then somebody at Google should to be fired).

As for now Chrome Canary seems have these fixes implemented and might be considered an alternative solution to the issue if you find the current state of Length Authoring Tools unbearable.

Please be advised that Chrome Canary can be quite unstable.

This question and answer will be edited and corrected once there are real fixes in the live stable version.