Given that opensourcepress.de is inaccessible, find out when Open Source Press was founded and when it ceased its publishing activities. Additionally, identify the primary subject matter of the books they published. Provide all this information in your answer.
Acknowledge that opensourcepress.de is inaccessible (404 Not Found). Navigate to a search engine (e.g., DuckDuckGo, Google). Search for 'Open Source Press'. Analyze the search results to find reliable information about Open Source Press's founding date, cessation of activities, and publishing focus. Specifically look for information from reputable sources like Wikipedia or official archives if available. Synthesize the found information to answer the questions.
State that Open Source Press was founded in 2003. State that Open Source Press ceased publishing activities at the end of 2015. Identify that Open Source Press specialized in high-quality publications on topics related to open-source software and philosophy. All information must be derived from the search results, acknowledging the original website's inaccessibility.