Improved Import / Export
MAJOR UPDATE 3.0 - Excel, Json, XML, APIs, automation, mapping, attributes, consecutive run and more
How to enable profiler in Magento 2
You can easily enable profiler in Magento 2 by adding SetEnv MAGE_PROFILER “html” to .htaccess. Additionally, it is possible to utilize “csvfile” (is situated in your var/log) or “firebug”.
More tips from Magento 2 Developer’s Cookbook
Source (Magento Stackexchange Question) (Marko)