I have observed that the Find/Replace feature in Ignition Designer omits a few key locations in its search procedure. This became evident to me as I started an Ignition gateway configuration for a new site by restoring a backup from a similar site, then used Find/Replace to find and replace all site specific references. These locations stood out as getting ignored/omitted completely by the search operation.
Gateway event scripts: Specifically scripting under Gateway Scheduled Scripts. I have not tested/confirmed all the other gateway event script locations.
Perspective Page Configuration: Specifically Page Title, I have not tested/confirmed all the other page fields (Page URL and Primary View).
I also found that search and replace will find but not replace tag values. That was annoying for me as we use tags (and specially crafted UDT instances) in some places to store alarm configuration that is shared (using tag binding) by multiple other tags. Specifically we have paths for Alarm Notification Pipelines stored in Memory String tags that were referenced by tag bindings in multiple other tags. Since the alarm notification path includes the project name (in our case that is site specific) we had to change all those manually. We could find those using the Find feature, but they were greyed out and we could not replace the values using Replace feature of that same tool.