[MacPorts] #60234: stlink @1.6.0 Sync with upstream - mechanism explanation needed

[MacPorts]

#60234: stlink @1.6.0 Sync with upstream - mechanism explanation needed
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 Reporter:  chenguokai  |      Owner:  (none)
     Type:  update      |     Status:  new
 Priority:  Normal      |  Milestone:
Component:  ports       |    Version:
 Keywords:              |       Port:  stlink
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 I checked the upstream and found new versions of stlink is available.
 I found no maintainers for this port and I wanted to take it if possible.
 However, I am quite confused with the portfile mechanism of this port.

 After reading the wiki, I know that this portfile specifies a Github Repo
 from which the port system obtains source code. While there are two
 problems left for me.

 1. I tried editing portfile locally, changing the version number but port
 would only try fetching the source code from mirrors of MacPorts, rather
 than fetch directly from Github upstream. Is there a way for me to test my
 modifications locally? And how does the mirroring mechanism work? If one
 changed the portfile configuration and merged into port tree, would the
 mirrors be synced automatically?
 2. I cannot figure out to whom the checksums belongs. I downloaded all
 1.6.0 source code from Github release page while none of them matches the
 checksum specified in the portfile. How can I obtain the file with the
 expected checksum from Github (not from mirrors because I intend to make
 an upgrade afterwhile so that I should provide checksums ahead)

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Ticket URL: <https://trac.macports.org/ticket/60234>
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