I can't replicate the examples given in the README regarding showall.
What I get:
julia> using DoubleFloats
julia> Double64(0.2)
0.2
julia> showall(ans)
0.2
julia> Double64(2)/10
1.99999999999999999999999999999999384e-01
julia> showall(ans)
1.99999999999999999999999999999999384e-01
This is using Julia 1.10.0.