Peaceable Projects Inc. is a U.S.-based non-profit group that brings the vast resources of the wide world together with the ongoing needs of the people who live, work, and travel on the Camino de Santiago pilgrim trail network in Spain.
I have never seen this app before and know nothing about it. But obviously safety is always a concern. I don't know which Camino you are planning but you can download Wise Pilgrim, Buen Camino or Camino Ninja. They are all safe and free and very good.
More seriously, Gerald Kelly, the app owner is a well known author with several guides for sale; including in the forum bookstore. I have actually got the app on my phone (although I use wise pilgrim and gronze) and have no reason to be concerned.
I agree that the landing page is a bit odd, but clicking on the link to Via de la Plata takes me to the Gerald Kelly app on Google Play, which I have had on my phone for years now. Perhaps @geraldkelly will see this thread and explain the different names.
caminoapp.net is my website, as others have pointed out.
I created it because I wanted to have a short URL which brings you straight to a link to either the Android or iPhone app store depending what kind of phone you open the URL on.
All my apps are available through the app stores for both phone types in the same way as any other app. To get on the app stores they have to comply with Apple's or Google's terms and conditions and be tested for malware or any other kind of security problem.
If anyone has any more questions please just ask.