We wrote a detailed blog post about just this. You can find it here
'Malli' means model, design or mockup in Finnish, a nordic language.
Malli handpicks the best free mockups that designers and agencies have put online. The mockups are sources from all over the internet. Since we do not want to cannibalize on someone else's work, we redirect you to the original owner of the mockup, but only to sites where you aren't redirected again or have to fill in a ton of shit just to download your mockup. This one redirect is necessary to support the original creator and the designer community in general.
Aha! We handpick high-quality free mockups from all over the internet and link them right back to you. Is there a mockup of yours is on our site, you did an amazing job. If you do not want your mockup to be up here. You can send us an email asking us to take it down, we'll do so immediately after you've proven it to be your mockup. You can do so on this email address: email@example.com
Yes. Every mockup on this site is checked and approved by us.
Oh.. The owner of the website must have deleted or moved the page. We're sorry. There's nothing we can do. You can always send us an email to report this so we can take it down.
We make sure every single mockup in our collection can be used for private, as well as commercial use. So in general, yes, you can. Beware: we only check these mockups once. If the owner of the mockup changes this after we've checked, then of course you can't so make sure to check.