'Other' is not always junk or useless files, but we recommend removing the useless content from this category.

Everything else that does not fit into the main macOS categories.

Various file and file types not recognized by Spotlight.

Cache items (browser cache, system cache and locally-stored message media content).

User library items (Application Support, iCloud files, screen savers, etc.).

System folders of macOS, (temporary files, swap, voices, etc.).

Archives and disk images, (zips, dmg, iso, etc.).

Documents and file types, (PDF, doc, PSD, etc.).

It is a very broad list of items, including things like the following: Over time, it can slow down computer performance.

These files are not harmful to your Mac but if they accumulate too much space to your hard drive.

This is the space taken up by plug-ins, documents, and caches stored by OS X. The Other storage on your Mac is composed of files that do not fall into clearer category labels: “applications, backups, audio, movies, backups, and photos”.

How to clear a mac hard drive