ΔE 6.6, close: similar, with a visible difference side by side. Umberroot is a little lighter, more saturated, cooler than Brown Base FS-30108.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Umberroot is a little lighter, more saturated, cooler than Brown Base FS-30108.
The same difference applies the other way round: Brown Base FS-30108 is a little darker, more muted, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Brown Base FS-30108 on the colour wheel See Umberroot on the colour wheel
All matches: Brown Base FS-30108 equivalents · Umberroot equivalents