In each file/submodule in the folder view and all its subfolders there's a function with name ending by theses 3 characters _ui. These functions are intended to be compiled from R code into the HTML/JS code, and as such they are going to be front end, visible to the users of the app. Try to wrap each potentialy in GUI visible texts with the function i18n$translate(" ... visible text here ...").
Example (file honeybee_info.R):
From this code
tags$p(
"Source code and scripts of the pDT can be found at ",
tags$a(icon("github"), "https://github.com/BioDT", href = "https://github.com/BioDT", target = "_blank"),
"."