What’s the difference between blockchain engineers, Solidity contract engineers, backend engineers etc.

I'm a software developer and I'm looking to transition into blockchain. When I browse through available roles in some companies, I see different titles such as:

• blockchain engineers
• Solidity contract engineers
• backend engineers etc.

Could someone describe the differences between these (and other career paths) for me please? I Googled but I found no relevant results.

P.S. X-posted on /r/ethereumnoobies