Applying the singulinkfx template to the docfx json build here: DevTKSS/DevTKSS.Uno.SampleApps#11
And then serve it locally, all alertboxes are not rendered as to be extended. Like with the Note, Tip and so on styling we know of for example GitHub or docfx own documentation.
Hoping you might can check on this? If I comment the template out like on latest commut on the branch so its only using the default and modern template, this is doing just fine.