This is a callout marker. Like all ChartIQ markers, the object itself is managed by the chart, so when you scroll the chart the object moves with you. It is also destroyed automatically for you when the symbol is changed. This is an example of a complex marker which can contain html, video, images, css, and animations.
Indices are designed to be broad measures of performance of an asset class or a subset of that asset class. So that indices are widely adopted, the methodology used to create an index is often published to give stakeholders an understanding of how decisions governing index calculation are made.
To able to the index numbers we most know what a price index is, how it is constructed, and how it is interpreted. A price index is a measure of price changes using a percentage scale. A price index can be based on the prices of a single item or a selected group of items, called a market basket.