The EOS 600D/Rebel T3i came out in 2011. At that time most of Canon's range of EOS bodies were compatible with changeable focusing screens.

Since then Canon has integrated electronic display indicators embedded into the focusing screens of many EOS bodies beginning around 2012-2014.

The 100D/SL1 is a 2013 model. That's right around the time that Canon made the change in their 5D and 7D lines, with which I am more familiar. But looking at genuine Canon replacement focusing screens for the Rebel SL1/100D, it does not appear the Rebel SL1/100D has any electronic connections embedded in the focusing screen.

Looking at the Rebel SL1/100D Manual, there are no alternative focusing screens listed in the accessories offered by Canon. In the Specifications, Canon lists the focusing screen as "fixed'. This means they consider it a non-user serviceable part.

The Canon Ec-L you linked to is for the EOS 1-Series 35mm film cameras and will not fit your APS-C digital camera.

There are a handful of third party makers that made manual focusing screens for the EOS Rebel SL1/100D. Most come with detailed instructions on how to do the swap yourself. But be aware they are not officially supported by Canon, and they may affect the accuracy of the camera's light meter, which is embedded in the pentamirror above the focusing screen. This can be offset using Exposure Compensation, but you'll need to do some trial and error to decide exactly how much EC you'll need to apply.

This one include a tweezer type tool to aid in installation.