Doing so would be confusing in frameworks like VelocityTools that use a ContextTool to do so. The ContextTool also provides several usefull Context introspection methods.

And it's a single line Java call to do this:
context.put("zeContext", context);

Most frameworks using Velocity provide a way to customize the context in one way or the other.

The problem is some products using Velocity do not provide any way to customise the context.
For example Maven.

I see.
And a "maven velocity customize context" search leads to two unanswered stackoverflow questions, so it may be worth...

would a properties file solution be enough?

Fixed in 2.x.
The new configuration property context.autoreference.key allows to specify the key under which the context will be put in itself.

I'm not sure, but I think jsr233 (or whatever the name of the java scripting API) actually requires that the context is available under the context binding/variable.

That should be sufficient for debugging.

You are right, the spec says:

In all cases, the ScriptContext used during a script execution must be a value
in the Engine Scope of the ScriptEngine whose key is the String “context”

So it's not exactly an autoreference key, but it's close: the ScriptContext contains nested scoped Bindings, plus references to the reader, the writer and the errorReader, and it should be visible its own engine scope bindings.

But it should be enforced, and after a little check it appears our implementation was not correct because I took the liberty of renaming the key to 'script_context'. I fixed it.