Eclipse Platform defines the set of frameworks and common services that collectively make up infrastructure required to support the use of Eclipse as a component model, as a Rich Client Platform (RCP) and as a comprehensive tool integration platform. These services and frameworks include a standard workbench user interface model and portable native widget toolkit, a project model for managing resources, automatic resource delta management for incremental compilers and builders, language-independent debug infrastructure, and infrastructure for distributed multi-user versioned resource management.
See also https://projects.eclipse.org/projects/eclipse.platform and https://eclipse.org/eclipse
The Eclipse Platform project is split into multiple Git repositories, which are all part of this organization. If you face an issue and have a sense of which particular GitHub repository is most related, you can open your issue against that repository. If you're unsure, you can open an issue against this current repositories and the issue will then be moved as best by maintainers.
e.g.
Contributions are always welcome!
Please bear in mind that this project is almost entirely developed by volunteers. If you do not provide the implementation yourself (or pay someone to do it for you), the bug might never get fixed. If it is a serious bug, other people than you might care enough to provide a fix.