I have just sent them the following email:
We heard that you are likely to sponsor Open Source projects. Our stickers were previously printed by UnixStickers but they have stopped this activity. We are looking for another sponsor.
Our project is Hoa, https://hoa-project.net. This is a set of PHP libraries. Recently, we have reached 4,5 millions of installations. Major vendors are using our project, like Mozilla, ownCloud, wallabag, fruux, Doctrine etc.
We need stickers to cover events. We also have an online shop (more or less a portal to real shops) at https://www.hoa-project.com/.
If you are likely to sponsor our project, first thanks! and second, your logo will appear on the homepage of our website, in the majority of our presentations/talks/keynotes, and on the homepage of our shop. Moreover, we will write a gratifying blog post about it.
Thank you very much, and have a good day!
I will keep you updated as soon as they reply.