Please point out any shortcuts missed! Also, all corrections welcome. Thanks HATMAN for quite a few.
1. "45" on c89: 2 outies r1c67 = 3 innies r367c8. Min. 3 innies = 6 -> min. r1c67 = 6
1a. 30,3(6)cages at r1c6 must have a 3(2) = {12}
1b. but the 3(2) can't be at r1c67 (step 1), must be at r12c9 or r2c89
1c. -> {12} locked for n3
1d. r2c9 = (12)
1e. 30(4) at r1c6 = {6789} -> r1c678 = (6789); r1c9 and r2c8 no 4 or 5
2. The 29,4(6) at r6c9 must have a 4(2) = {13} cage.
2a. Generalized X-wing on 1's in c89 with 3(2)n3: 1s locked for c89.
3. The 15,3(5) at r6c7 must have a 3(2) = {12} cage. Can't be at r67c8 (no 1) -> must be at r6c78 -> = [12]
3a. r7c78+r8c7 = 15(3) cage (note: can still have 2 in r78c7).
[edit after HATMAN's 2nd following post: need this bit to make step 4 work:
3b. "45" on n9: 1 remaining outie r6c9 - 3 = 1 innie r9c7. Min. r6c9 = 5, max. r9c7 = 6]
4. The 29,4(6) at r6c9 must have a 4(2) = {13} cage which only be at r89c8 or r9c89 [edit: can't be at r67c9 because no 1,3 in r6c9]: 1 & 3 both Locked for n9
4a. r9c8 = (13)
4b. 29(4) = {5789} -> r678c9 = (5789); r8c8, r9c9, no 2,4,6
5. 25,12(6) cages at r5c1 must be 25(4) and 12(2) since max. any 3 cells is 24 -> r5c12 = 12(2) (no 1,2,6)
6. "45" on r6789: 2 remaining outies r5c45 - 2 = 2 innies r6c69 -> min. r5c45 = 10
6a. 21,4(6) at r5c4 must have a 4(2) = {13} cage which cannot be at r5c45 (step 6) but must be at r45c4 (=[13]) or r7c56
6b. -> no 1,3 in common peers in r789c4 nor 3 in r7c7 (from diagonal /)
7. 14,5(5) at r7c2 must have a 5(2) cage (since min. any 3 cells is 6) = {14/23} = [1/3..]
7a. 5(2) can only be at r8c34 since no 1 nor 3 available in r78c4 -> r8c34 = [14/32]
7b. r7c234 = 14(3) cage
8. "45" on c12: 3 outies r6c3 + r9c34 - 13 = 3 innies r347c2 -> min. 3 outies = 19 and min. r9c34 = 10
8a. -> 28,5(6) at r8c1, which must have a 5(2) cage that can only be at r89c1 or r8c12 = {14/23} = [1/3..]
8b. r8c1 = (1234)
8c. 28(4) cage = {4789/5689} -> r9c234 = (4..9)
9. Killer pair 1,3 in implied 5(2)n7 (step 8a) and with r8c3: 1 & 3 both locked for n7
10. hidden pair 1,3 in r7 in r7c56: both locked for n8 (but not for 21,4(6) at r5c4!)
11. r7c234 = 14(3) (step 7b) = {248/257}(no 6,9)
11. 2 locked for r7
This next one is probably not needed but it is really fun so have put it in anyway.
12. one of the 5(2) cages in n7 (implied 5(2) and at r8c34) must have 2 (Locking cages); and the 14(3) at r7c234 must have 2 -> 2 locked at r78c4 for n8 and c4
13. "45" on n78: 1 remaining innie r7c1 - 5 = 1 outie r9c7 = [72/94]
13. "45" n9: 1 remaining outie r6c9 - 3 = 1 innie r9c7
13a. r6c9 = 5,7
14. There must be a 29(4) cage at r6c9 = {5789} with 8 & 9 only in n9: both locked for n9
15. 6 in r7 only in r7c78 in 15(3) cage
15a. 6 locked for n9
15b. 15(3) = 6{27/45}: no 7 in r8c7 since 2 must go there.
16. "45" on r89: 3 remaining innies r8c79 + one of r8c8/r9c9 = 19 = [2]{89}/[4]{78}(no 5 in any of those four possible cells)
16a. 8 locked for n9
16b. 5 in 29(4) at r6c9 only in c9: 5 locked for c9
17. naked pair {24} at r89c7: 4 locked for n9 & c7
17a. naked pair {24} at r8c47: both locked for r8
18. implied 5(2) at r8c1 = {14/23}, must have 2 or 4 which are only available at r9c1 -> r9c1 = (24)
18a. r89c1 = 5(2) -> no 1,3 in r8c2
19. 4 & 8 in r7 only in h14(3) at r7c2 = {248} only
19a. 8 blocked from r7c4 since {24} in n7 would clash with r9c1
20. 8 in r7 only in n7: locked for n7
21. naked pair {24} in r9c17: 4 locked for r9
22. 28(4) at r8c2 = {5689}(no 7)
22a. -> r9c4 = 8
23. hidden single 7 in n7 at r7c1
23a. no 7 in r6c23 (part of 28(4) cage
24. naked pair {56} = 11 at r7c78: 5 locked for r7
24a. and r8c7 = 4 (h15(3) cage sum)
24b. r9c7 = 2
25. "45" on n9: 1 remaining outie r6c9 = 5
26. r78c4 = [42]
27. r89c1 = [14] (h5(2) cage sum); note, 4 placed for D/
28. r8c3 = 3, r7c9 = 9
29. naked pair {78} at r8c89: 7 locked for r8 & n9
30. 7 in r6 only in n5: 7 locked for n5
As far as I can see, it's still not cracked! This next move was available near the beginning so it's needed after all.
31. The 17,7(5) at r3c9, min. any three cells is greater than 7 -> must have a 17(3) & 7(2) cage.
31a. The 7(2) can only be {34} at r45c8 or r5c89 -> r5c8 = (34)
31b. 3 and 4 locked for n6
32. 3 in c7 only in r23c7: locked for n3
33. "45" on n6: 1 outie r3c9 + 13 = 2 remaining innies r45c7
33a. max. r45c7 = 17 -> r3c9 = 4
33b. r45c7 = 17 = {89}: both locked for n6 & c7
34. "45" on n568: 2 remaining innies r4c45 = h12(2) = {39} only: both locked for n5 and r4
35. r45c7 = [89]
36. r3c7 = 3 (hidden single D/)
37. 4 on D\ only in r2c2 or r6c6 -> no 4 in r2c6 nor r6c2 (CPE)
37a. 4 in c6 only in r56c6: locked for n5
37b. and 4 locked in h12(3) (cages sum) at r456c6 = 4{17/26}(no 5,8)
38. we now know the 21,4(6) at r5c4 cannot have a 4(2) at r56c4 -> r7c56 is the 4(2) and r56c45 = 21(4)
38a. the 21(4) must have 8 for n5 = 8{157/256} = 6/7, not both -> no 6 or 7 in r5c45 or r6c5
38b. r6c5 = 8
39. 5 in n5 only in r5: 5 locked for r5
40. 12(2) at r5c12 = [84]
41. r4c8 = 4 (hidden single r4)
41a. r6c6 = 4 (hidden single n5) (placed for D\)
41b. r5c8 = 3
41c. r9c89 = [13] (3 placed for D\)
Just trying to get it to singles.
42. The 28,5(6) at r1c1 must have a 5(2). It can only be at r1c12 or r12c2 since min. r34c1 = 7.
42a. no 4 is available -> must be {32} -> R1C2 = 3
43b. 28(4) at r1c1 = {5689} -> r2c2 = 8 (placed for D\)
43c. r1c1 = 2 (5(2) cage sum) (placed for D\)
43d. r234c1 = {569}: all locked for c1 and 9 locked for n1
44. r6c4 = 7 (hsingle r6) (placed for D/)
45. hidden pair 2,6 in r45c6: both locked for c6
46. "45" on c6789: 2 outies r89c5 - 12 = r7c6 -> min. r89c5 = 13
46a. 18,11(5) at r8c5 must have an 11(2) cage which can't be at r89c5 (step 46) -> must be at r8c56 -> r8c56 = [65]
47. r8c2 = 9 (placed for D/)
47a. r2c8 = 6 (placed for D/)
48. 17,9(5) at r1c6 cannot have a 17(2) = {89}at r23c6 (blocked by ALS block at r19c6 = (789), and cannot have a 17(2) nor 9(2) at r2c67 (permutations) -> r23c6 must be 9(2) -> r23c6 = [18]
rest is naked singles.