theme.json and block markup can accept a wide range of values that can't (and probably shouldn't appear in the Gutenberg UI. For example:

• CSS variables
• calc()
• clamp()
• min()
• max()
• minmax()
• etc.

All of these are valid block markup. When they are used, Gutenberg currently just shows an empty form field in the UI. For example, here's some sample markup that uses a max() value for padding:

<!-- wp:group {"style":{"spacing":{"padding":{"top":"max(1.25rem, 5vw)","right":"max(1.25rem, 5vw)","bottom":"max(1.25rem, 5vw)","left":"max(1.25rem, 5vw)"}}},"backgroundColor":"foreground","textColor":"background"} -->
<div class="wp-block-group has-background-color has-foreground-background-color has-text-color has-background" style="padding-top:max(1.25rem, 5vw);padding-right:max(1.25rem, 5vw);padding-bottom:max(1.25rem, 5vw);padding-left:max(1.25rem, 5vw)"><!-- wp:paragraph -->
<p>Hello</p>
<!-- /wp:paragraph --></div>
<!-- /wp:group -->

Result:

We don't want to display these exact CSS calculations, since that'll be too complicated for the user. But we also shouldn't show a blank form field, since the user doesn't know that there's actually a value there. Is there something else we can display in cases like this?