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Arduino libraries may specify dependencies on other libraries in their metadata. The Arduino Library Manager offers the
option to install these dependencies when the user installs the library.

By default, the latest version of the dependency is installed. However, libraries may be compatible or tested working
only with specific versions of a dependency. In this case, the library developer may wish to specify a particular
version or version range of the dependency.

Arduino CLI and the Arduino Library index system has had support for such dependency version constraints for the last
2.5 years, but it was never documented so has only been used by the few library developers who discovered it via other
means.

The dependencies version constraint system is hereby fully documented in the Arduino library specification. This will
allow meaningful benefit to finally come from the work done to add this valuable capability.