This is a sort of "power strip" for a plug-in that others can take advantage of by declaring an extension to it.

这是插件的某种“电源板”，通过对插件声明扩展，其它插件就可以利用这个插件。

youdao

They also, in a smart bit of PR, launched a browser plug-in for Twitter users who wanted to strip out any mention of SXSW from their social media stream during March this year.

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