Many of the icons were displaying as empty boxes because:
https://www.nerdfonts.com/cheat-sheet
With Release v3.0.0 the Material Design Icons were updated and moved to new codepoints (reasons for that are in the release notes).
They are still shown here for reference, but are missing in the actual fonts.
To find for example the replacement for nf-mdi-altimeter enter just altimeter in the search box.
I updated them to the new codepoint. For example f85a became f035b.
Many of the icons were displaying as empty boxes because:
https://www.nerdfonts.com/cheat-sheet With Release v3.0.0 the Material Design Icons were updated and moved to new codepoints (reasons for that are in the release notes). They are still shown here for reference, but are missing in the actual fonts. To find for example the replacement for nf-mdi-altimeter enter just altimeter in the search box.
I updated them to the new codepoint. For example f85a became f035b.
This is mentioned in these issues https://github.com/Chick2D/neofetch-themes/issues/54 https://github.com/Chick2D/neofetch-themes/issues/55