[General Questions and Answers] cilyrik:
Trying to follow some 4-6 years old online guides & QnAs (mostly written by Irfan Latif) on how to backup stock ROM & partitions using adb pull or adb exec-out.

All of these materials always reference an mmcblk0 partition. But in my case it is missing.

What I have instead are these:

$ adb -s XXXXXXXX shell 'ls -al /dev/block' | grep -e '^[^d]'
total 0
lrwxrwxrwx 1 root root 37 1970-04-15 15:06 bootdevice -> /dev/block/platform/soc/XXXXXXX.ufshc
brw------- 1 root root 7, 0 1970-04-15 15:06 loop0
brw------- 1 root root 7, 8 1970-04-15 15:06 loop1
brw------- 1 root root 7, 80 1970-04-15 15:06 loop10
brw------- 1 root root 7, 88 1970-04-15 15:06 loop11
brw------- 1 root root 7, 96 1970-04-15 15:06 loop12
brw------- 1 root root 7, 104 1970-04-15 15:06 loop13
brw------- 1 root root 7, 112 1970-04-15 15:06 loop14
brw------- 1 root root 7, 120 1970-04-15 15:06 loop15
brw------- 1 root root 7, 16 1970-04-15 15:06 loop2
brw------- 1 root root 7, 24 1970-04-15 15:06 loop3
brw------- 1 root root 7, 32 1970-04-15 15:06 loop4
brw------- 1 root root 7, 40 1970-04-15 15:06 loop5
brw------- 1 root root 7, 48 1970-04-15 15:06 loop6
brw------- 1 root root 7, 56 1970-04-15 15:06 loop7
brw------- 1 root root 7, 64 1970-04-15 15:06 loop8
brw------- 1 root root 7, 72 1970-04-15 15:06 loop9
brw------- 1 root root 1, 0 1970-04-15 15:06 ram0
brw------- 1 root root 1, 1 1970-04-15 15:06 ram1
brw------- 1 root root 1, 10 1970-04-15 15:06 ram10
brw------- 1 root root 1, 11 1970-04-15 15:06 ram11
brw------- 1 root root 1, 12 1970-04-15 15:06 ram12
brw------- 1 root root 1, 13 1970-04-15 15:06 ram13
brw------- 1 root root 1, 14 1970-04-15 15:06 ram14
brw------- 1 root root 1, 15 1970-04-15 15:06 ram15
brw------- 1 root root 1, 2 1970-04-15 15:06 ram2
brw------- 1 root root 1, 3 1970-04-15 15:06 ram3
brw------- 1 root root 1, 4 1970-04-15 15:06 ram4
brw------- 1 root root 1, 5 1970-04-15 15:06 ram5
brw------- 1 root root 1, 6 1970-04-15 15:06 ram6
brw------- 1 root root 1, 7 1970-04-15 15:06 ram7
brw------- 1 root root 1, 8 1970-04-15 15:06 ram8
brw------- 1 root root 1, 9 1970-04-15 15:06 ram9
brw------- 1 root root 8, 0 1970-04-15 15:06 sda
brw------- 1 root root 8, 1 1970-04-15 15:06 sda1
brw------- 1 root root 8, 10 1970-04-15 15:06 sda10
brw------- 1 root root 8, 11 1970-04-15 15:06 sda11
brw------- 1 root root 8, 12 1970-04-15 15:06 sda12
brw------- 1 root root 8, 13 1970-04-15 15:06 sda13
brw------- 1 root root 8, 14 1970-04-15 15:06 sda14
brw------- 1 root root 8, 15 1970-04-15 15:06 sda15
brw------- 1 root root 259, 0 1970-04-15 15:06 sda16
brw------- 1 root root 259, 1 1970-04-15 15:06 sda17
brw------- 1 root root 259, 2 1970-04-15 15:06 sda18
brw------- 1 root root 259, 3 1970-04-15 15:06 sda19
brw------- 1 root root 8, 2 1970-04-15 15:06 sda2
brw------- 1 root root 259, 4 1970-04-15 15:06 sda20
brw------- 1 root root 259, 5 1970-04-15 15:06 sda21
brw------- 1 root root 259, 6 1970-04-15 15:06 sda22
brw------- 1 root root 259, 7 1970-04-15 15:06 sda23
brw------- 1 root root 8, 3 1970-04-15 15:09 sda3
brw------- 1 root root 8, 4 1970-04-15 15:06 sda4
brw------- 1 root root 8, 5 1970-04-15 15:06 sda5
brw------- 1 root root 8, 6 1970-04-15 15:06 sda6
brw------- 1 root root 8, 7 1970-04-15 15:06 sda7
brw------- 1 root root 8, 8 1970-04-15 15:06 sda8
brw------- 1 root root 8, 9 1970-04-15 15:06 sda9
brw------- 1 root root 8, 16 1970-04-15 15:06 sdb
brw------- 1 root root 8, 17 1970-04-15 15:06 sdb1
brw------- 1 root root 8, 18 1970-04-15 15:06 sdb2
brw------- 1 root root 8, 32 1970-04-15 15:06 sdc
brw------- 1 root root 8, 33 1970-04-15 15:06 sdc1
brw------- 1 root root 8, 34 1970-04-15 15:06 sdc2
brw------- 1 root root 8, 48 1970-04-15 15:06 sdd
brw------- 1 root root 8, 49 1970-04-15 15:06 sdd1
brw------- 1 root root 8, 50 1970-04-15 15:06 sdd2
brw------- 1 root root 8, 51 1970-04-15 15:06 sdd3
brw------- 1 root root 8, 52 1970-04-15 15:06 sdd4
brw------- 1 root root 8, 64 1970-04-15 15:06 sde
brw------- 1 root root 8, 65 1970-04-15 15:06 sde1
brw------- 1 root root 8, 74 1970-04-15 15:06 sde10
brw------- 1 root root 8, 75 1970-04-15 15:06 sde11
brw------- 1 root root 8, 76 1970-04-15 15:06 sde12
brw------- 1 root root 8, 77 1970-04-15 15:06 sde13
brw------- 1 root root 8, 78 1970-04-15 15:06 sde14
brw------- 1 root root 8, 79 1970-04-15 15:06 sde15
brw------- 1 root root 259, 8 1970-04-15 15:06 sde16
brw------- 1 root root 259, 9 1970-04-15 15:06 sde17
brw------- 1 root root 259, 10 1970-04-15 15:06 sde18
brw------- 1 root root 259, 11 1970-04-15 15:06 sde19
brw------- 1 root root 8, 66 1970-04-15 15:06 sde2
brw------- 1 root root 259, 12 1970-04-15 15:06 sde20
brw------- 1 root root 259, 13 1970-04-15 15:06 sde21
brw------- 1 root root 259, 14 1970-04-15 15:06 sde22
brw------- 1 root root 259, 15 1970-04-15 15:06 sde23
brw------- 1 root root 259, 16 1970-04-15 15:06 sde24
brw------- 1 root root 259, 17 1970-04-15 15:06 sde25
brw------- 1 root root 259, 18 1970-04-15 15:06 sde26
brw------- 1 root root 259, 19 1970-04-15 15:06 sde27
brw------- 1 root root 259, 20 1970-04-15 15:06 sde28
brw------- 1 root root 259, 21 1970-04-15 15:06 sde29
brw------- 1 root root 8, 67 1970-04-15 15:06 sde3
brw------- 1 root root 259, 22 1970-04-15 15:06 sde30
brw------- 1 root root 259, 23 1970-04-15 15:06 sde31
brw------- 1 root root 259, 24 1970-04-15 15:06 sde32
brw------- 1 root root 259, 25 1970-04-15 15:06 sde33
brw------- 1 root root 259, 26 1970-04-15 15:06 sde34
brw------- 1 root root 259, 27 1970-04-15 15:06 sde35
brw------- 1 root root 259, 28 1970-04-15 15:06 sde36
brw------- 1 root root 259, 29 1970-04-15 15:06 sde37
brw------- 1 root root 259, 30 1970-04-15 15:06 sde38
brw------- 1 root root 259, 31 1970-04-15 15:06 sde39
brw------- 1 root root 8, 68 1970-04-15 15:06 sde4
brw------- 1 root root 259, 32 1970-04-15 15:06 sde40
brw------- 1 root root 259, 33 1970-04-15 15:06 sde41
brw------- 1 root root 259, 34 1970-04-15 15:06 sde42
brw------- 1 root root 259, 35 1970-04-15 15:06 sde43
brw------- 1 root root 259, 36 1970-04-15 15:06 sde44
brw------- 1 root root 259, 37 1970-04-15 15:06 sde45
brw------- 1 root root 259, 38 1970-04-15 15:06 sde46
brw------- 1 root root 259, 39 1970-04-15 15:06 sde47
brw------- 1 root root 259, 40 1970-04-15 15:06 sde48
brw------- 1 root root 259, 41 1970-04-15 15:06 sde49
brw------- 1 root root 8, 69 1970-04-15 15:06 sde5
brw------- 1 root root 259, 42 1970-04-15 15:06 sde50
brw------- 1 root root 259, 43 1970-04-15 15:06 sde51
brw------- 1 root root 259, 44 1970-04-15 15:06 sde52
brw------- 1 root root 259, 45 1970-04-15 15:06 sde53
brw------- 1 root root 259, 46 1970-04-15 15:06 sde54
brw------- 1 root root 259, 47 1970-04-15 15:06 sde55
brw------- 1 root root 259, 48 1970-04-15 15:06 sde56
brw------- 1 root root 259, 49 1970-04-15 15:06 sde57
brw------- 1 root root 259, 50 1970-04-15 15:06 sde58
brw------- 1 root root 259, 51 1970-04-15 15:06 sde59
brw------- 1 root root 8, 70 1970-04-15 15:06 sde6
brw------- 1 root root 259, 52 1970-04-15 15:06 sde60
brw------- 1 root root 259, 53 1970-04-15 15:06 sde61
brw------- 1 root root 259, 54 1970-04-15 15:06 sde62
brw------- 1 root root 259, 55 1970-04-15 15:06 sde63
brw------- 1 root root 259, 56 1970-04-15 15:06 sde64
brw------- 1 root root 259, 57 1970-04-15 15:06 sde65
brw------- 1 root root 259, 58 1970-04-15 15:06 sde66
brw------- 1 root root 259, 59 1970-04-15 15:06 sde67
brw------- 1 root root 259, 60 1970-04-15 15:06 sde68
brw------- 1 root root 259, 61 1970-04-15 15:06 sde69
brw------- 1 root root 8, 71 1970-04-15 15:06 sde7
brw------- 1 root root 259, 62 1970-04-15 15:06 sde70
brw------- 1 root root 259, 63 1970-04-15 15:06 sde71
brw------- 1 root root 259, 64 1970-04-15 15:06 sde72
brw------- 1 root root 259, 65 1970-04-15 15:06 sde73
brw------- 1 root root 259, 66 1970-04-15 15:06 sde74
brw------- 1 root root 259, 67 1970-04-15 15:06 sde75
brw------- 1 root root 259, 68 1970-04-15 15:06 sde76
brw------- 1 root root 8, 72 1970-04-15 15:06 sde8
brw------- 1 root root 8, 73 1970-04-15 15:06 sde9
brw------- 1 root root 8, 80 1970-04-15 15:06 sdf
brw------- 1 root root 8, 81 1970-04-15 15:06 sdf1
brw------- 1 root root 8, 82 1970-04-15 15:06 sdf2
brw------- 1 root root 8, 83 1970-04-15 15:06 sdf3
brw------- 1 root root 8, 84 1970-04-15 15:06 sdf4
brw------- 1 root root 8, 85 1970-04-15 15:06 sdf5
brw------- 1 root root 8, 86 1970-04-15 15:06 sdf6
brw------- 1 root root 8, 87 1970-04-15 15:06 sdf7
brw------- 1 root root 8, 88 1970-04-15 15:06 sdf8
brw------- 1 root root 8, 89 1970-04-15 15:06 sdf9
brw------- 1 root root 254, 0 1970-04-15 15:06 zram0

Which one of those is the new mmcblk0? Which one should I pull to have a full backup of my device stock firmware as an .img file?