In short, she/they is the most common way for a person to indicate that they go by she/her or they/them pronouns, likely with a preference for the former. Taken from the free online dictionary: 为什么英语中女性 she 的宾格和所有格同是 her，而男性 he 的宾语和所有格却不同？ she：宾格 (her) 所有格 (her) he:
Soap She Knows Recaps at Debra Cunningham blog
4、安静了 梦想中属于我们的婚礼 安静了 这首歌，是周杰伦邀请she参观他的新公司时，当场写出来的。she《play》专辑里面的一首歌曲 《借口》 拼贴了周杰伦的许多歌名，周杰伦听.
According to grammar rules, it should be this is she, because is is a linking verb (a verb that connects the subject to more information about the subject), so it can't have an object (her), but it's.
In your example, she is being emphasised. 译成中文的话 her 和 she 都是她。 但这两个字的用法不一样。举个例子，你自己感受一下。 she killed someone last night 她昨晚杀了人。 someone killer her last night.
