You want to modify these items in the vIew toolbar?
If that's what you are after, you have to modify the buttons all tagged with $:/tags/ViewToolbar
Create a tiddler containing <<tag $:/tags/ViewToolbar>>
Click on the tagpill and you get a list of all tiddlers tagged with $:/tags/ViewToolbar
But know what you are doing.
My Customization guide (
http://tw5custom.tiddlyspot.com/) contains info about all kinds of buttons.
My Exploration guide (
http://tw5exploration.tiddlyspot.com/) let you explore the core tiddlers.
Cheers,
Ton