This keeps lines finishing with the specified text and discards everything else, matching only at the end of each line.
Why the end position matters
Meaningful markers frequently sit at the end of a value: file extensions, trailing slashes, currency codes, status suffixes. Anchoring there avoids matching the same characters elsewhere in the line.
The most common use
Isolating one file type from a mixed URL list — every PDF, every image, every feed.
The inverse
Removing lines by their ending is the same filter in the opposite direction, and which one to use depends only on whether the target set is the smaller one.
Try it: Keep Lines Ending With on SeoWolf's Notepad.