Earthly, an open-source build tool, is participating in this year's Hacktoberfest, an annual event hosted by DigitalOcean to celebrate open source, where participants are encouraged to submit pull requests to open source projects. Those who make four or more pull requests receive a free t-shirt from DigitalOcean, and Earthly is offering additional incentives, such as stickers for the first 40 participants who have a pull request accepted in Earthly’s GitHub Repository within the specified timeframe. Participants can also earn a sticker by adding a working Earthfile to another open-source project, with approval from project maintainers. For any questions or assistance, Earthly provides support via a Gitter channel and email.