If you are using free version of the library it will display the branding link.
In order to remove the link you will need to purchase a commercial license ($140 per website) and install the libraries on your server.
http://www.amcharts.com/online-store/
It seems to me that plugins published in the WordPress repository should comply with the restrictions?
https://ww.wp.xz.cn/plugins/about/
Restrictions
4. The plugin must not embed external links on the public site (like a “powered by” link) without explicitly asking the user’s permission.
Hi there.
The plugin is free and open source. It does not display any branding itself.
The branding is coming from external amCharts library which, when loaded freely off amChart’s servers displays a link.
Plugin user is free to choose the location and version of the actual charting library to be used.
