I just helped baconmeh2 write a userscript, and then they suggested I reply in this thread, so I list the description of the userscript:
DeviantArt filenames contain a base36-encoded post ID at the end (prefixed with "d"). For example, "15_vaati_icons_by_lavleyart_by_lavleyart_dix7cpg" contains "ix7cpg", which converts to "1144161556" in base10. You can directly access posts via "https://deviantart.com/view/1144161556".
This userscript automatically converts base36 IDs to base10 format URLs, allowing quick access to original posts from saved filenames.
Note: Everything from "-" onward in filenames (such as "-pre") are sample image suffixes and can be ignored.