List of Modification A320 FCOM
 

What exactly does ' list of modifications' on A320 FCOM indicates?

With the years, the airplane is modified. Each modification is registered.

For instance, there is a modification such that you don't have to push the ESS ALTN button when you have a AC BUS 1 failure. The reconfiguration is automatic since the mod, and you only push the button if the reconfiguration fails to occur automatically.

There are hundreds of them!

I am not sure of your explanation. if you have a close look at that list of modifications I am talking about, you will find entries that would contradict your explanation. for example, one entry talks about the installation of HONEYWELL FMGC and other entry talks about the installation of THALES FMGC. both entries show the incorporation date of oct 11. How is this possible?