While it’s true that most Eclipse projects use the Eclipse Public License, many Eclipse open source projects use alternative licenses either alone or in combination.
The chart below shows the relative use of various license schemes by Eclipse open source projects:
Note that we use SPDX expression. In SPDX, license combinations are expressed from the consumer’s point of view, so dual licensing is expressed using disjunctive “OR”. For example, “EPL-2.0 or Apache-2.0” expresses dual licensing of content under the Eclipse Public License 2.0 or Apache License 2.0. Further, in SPDX, secondary licenses–as they are supported by the Eclipse Public License 2.0–are expressed as dual licensing; from the consumer’s point of view, our form of secondary licensing is equivalent to dual licensing. So, “EPL-2.0 or GPL-2.0 WITH Classpath-exception-2.0” indicates that the source code may be distributed under the Eclipse Public License 2.0, or the secondary license’s terms (there’s more information about secondary licensing in the FAQ).
When we filter out all but the Eclipse Public License, the graph simplifies to this:
Many of our older projects still use the Eclipse Public License 1.0. Project have been updating to version 2.0 over time. For those projects that haven’t updated yet: I’m coming for you.