What are the real life implications for an Apache 2 license? [closed]

Question

I want to use SVG Edit for a project. This software is distributed under the Apache 2 license.

I've seen that:

• all copies, modified or unmodified, are accompanied by a copy of the licence
• all modifications are clearly marked as being the work of the modifier
• all notices of copyright, trademark and patent rights are reproduced accurately in distributed copies
• the licensee does not use any trademarks that belong to the licensor

Do these pertain to the code or should I display the license somewhere in the GUI? The original software displays a "powered by SVG Edit", is it ok if I remove this? And most importantly: what is the correct etiquette for doing this? I don't want to be a jerk, but at the same time I want to simplify the UI as much as possible and removing the link will be part of it if it's not considered rude.