excerpt from modified twai_self_test_example_main.c

    ESP_ERROR_CHECK(twai_driver_install(&g_config, &t_config, &f_config));
    ESP_LOGI(EXAMPLE_TAG, "Driver installed");
    ESP_LOGI(EXAMPLE_TAG, "f_config.acceptance_code = 0x%08x\n", f_config.acceptance_code);
    ESP_LOGI(EXAMPLE_TAG, "f_config.acceptance_mask = 0x%08x\n", f_config.acceptance_mask);
    ESP_LOGI(EXAMPLE_TAG, "f_config.single_filter = 0x%08x\n", f_config.single_filter);

    ESP_LOGI(EXAMPLE_TAG, "acceptance_filter.acr[] =");
    for(int i=0; i<4; i++) {
        ESP_LOGI(EXAMPLE_TAG, " %02x", TWAI.acceptance_filter.acr[i].byte);
    }
    ESP_LOGI(EXAMPLE_TAG, "\n");
    ESP_LOGI(EXAMPLE_TAG, "acceptance_filter.amr[] =");
    for(int i=0; i<4; i++) {
        ESP_LOGI(EXAMPLE_TAG, " %02x", TWAI.acceptance_filter.amr[i].byte);
    }
    ESP_LOGI(EXAMPLE_TAG, "\n");

Excerpt from WIP CircuitPython CAN.c

    esp_err_t result = twai_driver_install(&self->g_config, &self->t_config, &self->f_config);
    if (result == ESP_ERR_NO_MEM) {
        mp_raise_msg(&mp_type_MemoryError, translate("ESP-IDF memory allocation failed"));
    } else if (result == ESP_ERR_INVALID_ARG) {
        mp_raise_ValueError(translate("Invalid pins"));
    } else if (result != ESP_OK) {
        mp_raise_OSError_msg_varg(translate("twai_driver_install returned esp-idf error #%d"), (int)result);
    }

    mp_printf(&mp_plat_print, "f_config.acceptance_code = 0x%08x\n", self->f_config.acceptance_code);
    mp_printf(&mp_plat_print, "f_config.acceptance_mask = 0x%08x\n", self->f_config.acceptance_mask);
    mp_printf(&mp_plat_print, "f_config.single_filter = 0x%08x\n", self->f_config.single_filter);
    mp_printf(&mp_plat_print, "acceptance_filter.acr[] =");
    for(int i=0; i<4; i++) {
        mp_printf(&mp_plat_print, " %02x", TWAI.acceptance_filter.acr[i].byte);
    }
    mp_printf(&mp_plat_print, "\n");
    mp_printf(&mp_plat_print, "acceptance_filter.amr[] =");
    for(int i=0; i<4; i++) {
        mp_printf(&mp_plat_print, " %02x", TWAI.acceptance_filter.amr[i].byte);
    }
    mp_printf(&mp_plat_print, "\n");

Output from above code 1.txt

I (324) TWAI Self Test: Driver installed
I (324) TWAI Self Test: f_config.acceptance_code = 0xca000000

I (334) TWAI Self Test: f_config.acceptance_mask = 0x01ffffff

I (334) TWAI Self Test: f_config.single_filter = 0x00000001

I (344) TWAI Self Test: acceptance_filter.acr[] =
I (344) TWAI Self Test:  ca
I (354) TWAI Self Test:  00
I (354) TWAI Self Test:  00
I (354) TWAI Self Test:  00
I (364) TWAI Self Test: 

I (364) TWAI Self Test: acceptance_filter.amr[] =
I (374) TWAI Self Test:  01
I (374) TWAI Self Test:  ff
I (374) TWAI Self Test:  ff
I (384) TWAI Self Test:  ff
I (384) TWAI Self Test: 

Output from above code 2.txt

f_config.acceptance_code = 0x00000000
f_config.acceptance_mask = 0xffffffff
f_config.single_filter = 0x00000001
acceptance_filter.acr[] = 5a 5a 5a 5a
acceptance_filter.amr[] = 5a 5a 5a 5a