Hello,
The easiest way is following:
1. Create new solution and add assembly that contains plugin source code of which you want to see.
2. Export solution. Unpack it and find assembly inside archive.
3. Use Reflector or ILSpy to find source code of plugin. There is a chance that code of plugin would be obfuscated and protected against disassembling. But anyway good luck!
Dynamics CRM MVP
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