/usr/include/linbox/field/ is in liblinbox-dev 1.3.2-1.1+b1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/linbox/field/Givaro/
/usr/include/linbox/field/Givaro/givaro-extension.h
/usr/include/linbox/field/Givaro/givaro-field-gf2.h
/usr/include/linbox/field/Givaro/givaro-field.h
/usr/include/linbox/field/Givaro/givaro-gfq.h
/usr/include/linbox/field/Givaro/givaro-montg.h
/usr/include/linbox/field/Givaro/givaro-rational.h
/usr/include/linbox/field/Givaro/givaro-zpz.h
/usr/include/linbox/field/Givaro/givaro-zpz.inl
/usr/include/linbox/field/Modular/
/usr/include/linbox/field/Modular/modular-balanced-double.h
/usr/include/linbox/field/Modular/modular-balanced-float.h
/usr/include/linbox/field/Modular/modular-balanced-int32.h
/usr/include/linbox/field/Modular/modular-balanced-int64.h
/usr/include/linbox/field/Modular/modular-byte.h
/usr/include/linbox/field/Modular/modular-crooked-double.h
/usr/include/linbox/field/Modular/modular-double.h
/usr/include/linbox/field/Modular/modular-float.h
/usr/include/linbox/field/Modular/modular-int32.h
/usr/include/linbox/field/Modular/modular-int64.h
/usr/include/linbox/field/Modular/modular-short.h
/usr/include/linbox/field/Modular/modular-unsigned.h
/usr/include/linbox/field/Modular/modular.inl
/usr/include/linbox/field/NTL/
/usr/include/linbox/field/NTL/ntl-GF2E.h
/usr/include/linbox/field/NTL/ntl-RR.h
/usr/include/linbox/field/NTL/ntl-ZZ.h
/usr/include/linbox/field/NTL/ntl-ZZ_p.h
/usr/include/linbox/field/NTL/ntl-ZZ_pE.h
/usr/include/linbox/field/NTL/ntl-ZZ_pX.h
/usr/include/linbox/field/NTL/ntl-lzz_p.h
/usr/include/linbox/field/NTL/ntl-lzz_pE.h
/usr/include/linbox/field/NTL/ntl-lzz_pX.h
/usr/include/linbox/field/PID-double.h
/usr/include/linbox/field/PID-integer.h
/usr/include/linbox/field/PID-ntl-zz_p.h
/usr/include/linbox/field/PIR-modular-int32.h
/usr/include/linbox/field/PIR-ntl-ZZ_p.h
/usr/include/linbox/field/abstract.h
/usr/include/linbox/field/archetype.h
/usr/include/linbox/field/block-ring.h
/usr/include/linbox/field/envelope.h
/usr/include/linbox/field/field-interface.h
/usr/include/linbox/field/field-traits.h
/usr/include/linbox/field/gf2.h
/usr/include/linbox/field/gf2.inl
/usr/include/linbox/field/givaro.h
/usr/include/linbox/field/gmp-rational.h
/usr/include/linbox/field/hom.h
/usr/include/linbox/field/local2_32.h
/usr/include/linbox/field/map.h
/usr/include/linbox/field/modular-balanced.h
/usr/include/linbox/field/modular.h
/usr/include/linbox/field/multimod-field.h
/usr/include/linbox/field/ntl.h
/usr/include/linbox/field/param-fuzzy.h
/usr/include/linbox/field/rebind.h
/usr/include/linbox/field/unparametric.h