Without more context, here are the most likely ways this is used:
: In many bulk download tools or browser extensions, this string indicates a summary of available files: 5 new files detected, with 3 in .txt format and the remainder likely in .html format . Download New (5) txt (3) html
: Look for the .txt extension in the source list. To find web pages : Look for the .html extension. Without more context, here are the most likely