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ONLYOFFICE
ONLYOFFICE Docs is a free collaborative online office suite comprising viewers and editors for texts, spreadsheets and presentations, forms and PDF, fully compatible with Office Open XML formats: .docx, .xlsx, .pptx and enabling collaborative editing in real time.
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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
OnlyOffice Docs is basically an open clone of Google Docs. It’s designed to be self hosted but you can run it on your PC
There is an open source tool called typst.app. It's in beta but it looks interesting. You can also write programatically if that is necessary.
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Hence, a higher number means a more popular project.