The 4th sigil was solved by combining clues from both .pdf files received by solving two passwords on Myriad-70:
- http://www.myriad-70.com/clients/017-a24 > star chart
- http://www.myriad-70.com/clients/021-f16/ > discovery
Each pdf contained a code:
- 017-a24 > 313-xxxxx
- 021-f16 > xxx-98176
Combining the above resulted in the solution for the 4th sigil > 313-98176
See the following topic for info solving the Myriad-70 puzzles:
https://forums.etarc.org/t/myriad-70-solve-thread/755