Accessibility user-scalable=0 vs user-scalable="no"

[raroul]

Hello !
I noticed that some sites are using the meta viewport with user-scalable attribute set to 0 <meta name="viewport" content="width=device-width, initial-scale=1.0, height=device-height, minimum-scale=1.0, user-scalable=0"> and still manage to get the accessibility test of the meta viewport passing.
Is it a trick to bypass the lighthouse test or setting the user-scalable attribute to 0 has a different effect that setting it to "no" ?

[patrickhulce]

Thanks for asking @raroul! You're right it appears the accessibility library that Lighthouse uses does not follow the spec, it just looks for user-scalable=no.

Related discussion in axe-core already suggests this isn't really a big deal anymore because major browsers either ignore this property by default of have an easy way for users to override this setting. You're welcome to file this gap over there along with the spec link I shared that 0 is treated as fixed, but I'm not sure they'd prioritize it :)