/usr/share/sdcc/include/mcs51/ is in sdcc-libraries 2.9.0-5.
This file is owned by root:root, with mode 0o755.
..
/usr/share/sdcc/include/mcs51/8051.h
/usr/share/sdcc/include/mcs51/8052.h
/usr/share/sdcc/include/mcs51/ADuC84x.h
/usr/share/sdcc/include/mcs51/C8051F000.h
/usr/share/sdcc/include/mcs51/C8051F018.h
/usr/share/sdcc/include/mcs51/C8051F020.h
/usr/share/sdcc/include/mcs51/C8051F040.h
/usr/share/sdcc/include/mcs51/C8051F060.h
/usr/share/sdcc/include/mcs51/C8051F120.h
/usr/share/sdcc/include/mcs51/C8051F200.h
/usr/share/sdcc/include/mcs51/C8051F300.h
/usr/share/sdcc/include/mcs51/C8051F310.h
/usr/share/sdcc/include/mcs51/C8051F320.h
/usr/share/sdcc/include/mcs51/C8051F326.h
/usr/share/sdcc/include/mcs51/C8051F330.h
/usr/share/sdcc/include/mcs51/C8051F336.h
/usr/share/sdcc/include/mcs51/C8051F340.h
/usr/share/sdcc/include/mcs51/C8051F350.h
/usr/share/sdcc/include/mcs51/C8051F360.h
/usr/share/sdcc/include/mcs51/C8051F410.h
/usr/share/sdcc/include/mcs51/C8051F520.h
/usr/share/sdcc/include/mcs51/C8051T600.h
/usr/share/sdcc/include/mcs51/C8051T610.h
/usr/share/sdcc/include/mcs51/C8051T630.h
/usr/share/sdcc/include/mcs51/P89LPC901.h
/usr/share/sdcc/include/mcs51/P89LPC922.h
/usr/share/sdcc/include/mcs51/P89LPC925.h
/usr/share/sdcc/include/mcs51/P89LPC932.h
/usr/share/sdcc/include/mcs51/P89c51RD2.h
/usr/share/sdcc/include/mcs51/SST89x5xRDx.h
/usr/share/sdcc/include/mcs51/XC866.h
/usr/share/sdcc/include/mcs51/at89S8252.h
/usr/share/sdcc/include/mcs51/at89c51ed2.h
/usr/share/sdcc/include/mcs51/at89c51snd1c.h
/usr/share/sdcc/include/mcs51/at89c55.h
/usr/share/sdcc/include/mcs51/at89s53.h
/usr/share/sdcc/include/mcs51/at89s8253.h
/usr/share/sdcc/include/mcs51/at89x051.h
/usr/share/sdcc/include/mcs51/at89x51.h
/usr/share/sdcc/include/mcs51/at89x52.h
/usr/share/sdcc/include/mcs51/cc1110.h
/usr/share/sdcc/include/mcs51/cc2430.h
/usr/share/sdcc/include/mcs51/cc2510fx.h
/usr/share/sdcc/include/mcs51/compiler.h
/usr/share/sdcc/include/mcs51/lint.h
/usr/share/sdcc/include/mcs51/mcs51reg.h
/usr/share/sdcc/include/mcs51/msc1210.h
/usr/share/sdcc/include/mcs51/msm8xc154s.h
/usr/share/sdcc/include/mcs51/p89c66x.h
/usr/share/sdcc/include/mcs51/p89lpc933_4.h
/usr/share/sdcc/include/mcs51/p89lpc935_6.h
/usr/share/sdcc/include/mcs51/p89lpc938.h
/usr/share/sdcc/include/mcs51/p89v51rd2.h
/usr/share/sdcc/include/mcs51/p89v66x.h
/usr/share/sdcc/include/mcs51/reg51.h
/usr/share/sdcc/include/mcs51/reg764.h
/usr/share/sdcc/include/mcs51/regc515c.h
/usr/share/sdcc/include/mcs51/sab80515.h
/usr/share/sdcc/include/mcs51/serial_IO.h
/usr/share/sdcc/include/mcs51/uPSD33xx.h