What does XLLS mean?

Is there some relation between "XLLS" expression and AJAX / Javascript? What does the XLLS actually mean?

Thanks in advance

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adding text from a com开发者_Python百科ment below an answer

...the only result I got when I was looking for an answer on Google was the Excel XLLs but nothing related to JS. It's because I'm learning for an exam and there is a question to describe acronym "XLLS". Maybe typo?

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Never heard of that in a Javascript context.

The only meaningful Google result I can see is Developing Excel 2010 XLLs

Sure you don't mean XSLT? or XSS?