Median and percentile functions are available as built-in functions for calculated metrics within Adobe Analytcs, but they are Table based,
From Adobe Documentation:
Table Functions versus Row Functions
A table function is one where the output is the same for every row of the table. A row function is one where the output is different for every row of the table.
See below example of table using the this functionality with one Median and one 90th Percentile metric.
The base metric that is calculated as median and 90th percentile is a Numeric metric. With Row capability for median and percentile, instead of having the median/percentile for all line items in total it would be possible to see the median for each individual row. Ie, what was the median/percentile for Feb 4, Feb 11, Feb18.
This functionality would be fantastic and help to calculate medians/percentiles directly in the Adobe interface without having to resort to large data exports and manual calculation. Useful for any Numeric metrics where you need to understand the distribution of the individual metric values (eg technical data such as load times, waiting times, or other numeric metrics such as sales numbers) across different dimension values.