The same key that is on the German FWL16 keyboard, correct?
frame.work/products/keyboard-module?v=FRAKDW00A7
What layout is your OS keyboard set to?
What character a key produces depends on the layout you have set. As keyboards just send a set of codes for their keys, and the OS is what really decides what a key will produce in different languages and layouts. You will get whatever is in that location on the keymap set in your OS. If the layout you have set not have the key you want, then you will not get it.
The FWL16 keyboard ISO layout from the firmware.
github.com/FrameworkComputer/qmk_firmware/blob/v0.2.9/keyboards/framework/iso/keymaps/default/keymap.c
* ┌─────┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬────┐
* 14 keys │Esc │Mut│vDn│vUp│Prv│Ply│Nxt│bDn│bUp│Scn│Air│Prt│App│ Del│
* ├───┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴────┤
* 14 keys │ ` │ 1 │ 2 │ 3 │ 4 │ 5 │ 6 │ 7 │ 8 │ 9 │ 0 │ - │ = │Backsp│
* ├───┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬────┤
* 13 keys │ Tab │ Q │ W │ E │ R │ T │ Y │ U │ I │ O │ P │ [ │ ] │Entr│
* ├─────┴┬──┴┬──┴┬──┴┬──┴┬──┴┬──┴┬──┴┬──┴┬──┴┬──┴┬──┴┬──┴┐ │
* 14 keys │ Caps │ A │ S │ D │ F │ G │ H │ J │ K │ L │ ; │ ' │ # │ │
* ├────┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴─┬─┴───┴───┤
* 13 keys │Shft│ \ │ Z │ X │ C │ V │ B │ N │ M │ , │ . │ / │ Shift │
* ├────┼───┼───┼───┼───┴───┴───┴───┴───┼───┼───┼───┴┬───┬────┤
* │ │ │ │ │ │ │ │ │↑ │ │
* 11 keys │Ctrl│FN │GUI│Alt│ │Alt│Ctl│ ← ├───┤ → │
* │ │ │ │ │ │ │ │ │ ↓│ │
* └────┴───┴───┴───┴───────────────────┴───┴───┴────┴───┴────┘
* 79 total
*/
[_BASE] = LAYOUT(
KC_ESC, KC_MUTE, KC_VOLD, KC_VOLU, KC_MPRV, KC_MPLY, KC_MNXT, KC_BRID, KC_BRIU, KC_SCRN, KC_AIRP, KC_PSCR, KC_MSEL, KC_DEL,
KC_GRV, KC_1, KC_2, KC_3, KC_4, KC_5, KC_6, KC_7, KC_8, KC_9, KC_0, KC_MINS, KC_EQL, KC_BSPC,
KC_TAB, KC_Q, KC_W, KC_E, KC_R, KC_T, KC_Y, KC_U, KC_I, KC_O, KC_P, KC_LBRC, KC_RBRC,
KC_CAPS, KC_A, KC_S, KC_D, KC_F, KC_G, KC_H, KC_J, KC_K, KC_L, KC_SCLN, KC_QUOT, KC_NUHS, KC_ENT,
KC_LSFT, KC_NUBS, KC_Z, KC_X, KC_C, KC_V, KC_B, KC_N, KC_M, KC_COMM, KC_DOT, KC_SLSH, KC_RSFT,
KC_LCTL, MO(_FN), KC_LGUI, KC_LALT, KC_SPC, KC_RALT, KC_RCTL, KC_LEFT, KC_UP, KC_DOWN, KC_RGHT
All ISO keyboards use the same firmware and will send the same keycode for that key.
NUBS
aka NONUS_BACKSLASH
: “Non-US \
and |
” is what that key will send. github.com/qmk/qmk_firmware/blob/master/docs/keycodes_basic.md?plain=1#L96
If you don’t want to change the layout you have set in your OS to a layout which has the key you want in that location on it’s keymap, then you’ll have to use other methods to input the character. unicode-explorer.com/articles/how-to-type-unicode-characters-in-linux. You can put the unicode entry into a macro. Creating a custom layout within your OS just for your use is another option. I’ve looked at that in the past, but I don’t recall the details, where the config files are in the distro I use, etc.