Error when trying to access "extra" in page

So I have markdown files that all have an “extra” field like this:

extra:
  masto: https://xxxx

When I try accessing this field form a template html file and I view the __tera_context variable, I see this in there:
"extra": { "masto": "https://xxxx" },

So it is available. When I access

{{ page.extra }} it prints [object]

Now, how do I access the inside of this object? I tried

{{ page.extra.masto }}
{{ page.extra[masto] }}
{{ page.extra["masto"] }}
{{ page.extra.get["masto"] }}
{{ page.extra | first }}

but everything returns an error. How do I get to the information?

Ok I figured out that I had to put a {%if page.extra.masto is defined %} around trying to access it because the field is not present on all pages.

My bad.