Time for some gentoo portage local overlay cleanup operation. Following ebuild files are obsolete and should not be displayed in portage:

user@host % eix gns3
* net-misc/gns3-gui
    Available versions:  (~)2.1.11-r1^t[1] (~)2.1.12-r1^t[1] (~)2.1.14-r1^t[1] (~)2.1.15-r1^t[1] (~)2.1.16-r1^t[1] (~)2.2.8 {PYTHON_TARGETS="python3_6 python3_7 python3_8"}
    Homepage:            https://www.gns3.net/
    Description:         Graphical Network Simulator

* net-misc/gns3-server
    Available versions:  (~)2.1.11-r1^t[1] (~)2.1.12-r1^t[1] (~)2.1.14-r1^t[1] (~)2.1.14-r2^t[1] (~)2.1.15-r1^t[1] (~)2.1.16-r1^t[1] (~)2.2.8 {PYTHON_TARGETS="python3_6 python3_7 python3_8"}
    Homepage:            https://www.gns3.net/
        Description:         GNS3 server to asynchronously manage emulators

[1] "testing" /usr/local/portage

GNS3 2.2.8 version has been released with python3_7 and python3_8 support. Time to get rid of gns3 2.1 version located in local gentoo overlay named testing. Files overview in the local overlay:

The goal is to rename all .ebuild files to .old suffix. That way ebuilds do not get indexed in portage, while remaining still preserved in the directory. Using a for loop and matching the filname suffix, each file in gets moved to the .old suffix. This is done on top of the current directory: /usr/local/portage/net-misc/gns3-gui.

for FILE in *.ebuild; do mv $FILE $FILE.old; done

Verify the result:

host # ls
gns3-gui-2.1.11-r1.ebuild.old  gns3-gui-2.1.14-r1.ebuild.old  gns3-gui-2.1.16-r1.ebuild.old
gns3-gui-2.1.12-r1.ebuild.old  gns3-gui-2.1.15-r1.ebuild.old  Manifest

Update portage index:

root@host # eix-update 
Reading Portage settings...
Building database (/var/cache/eix/portage.eix)...
[0] "gentoo" /usr/portage/ (cache: metadata-md5-or-flat)
     Reading category 168|168 (100) Finished             
[1] "testing" /usr/local/portage (cache: parse|ebuild*#metadata-md5#metadata-flat#assign)
     Reading category 168|168 (100) Finished         
Applying masks...
Calculating hash tables...
Writing database file /var/cache/eix/portage.eix...
Database contains 18914 packages in 168 categories

Search for the gns3 package using eix:

alpha ~ # eix gns3
* net-misc/gns3-gui
     Available versions:  (~)2.2.8 {PYTHON_TARGETS="python3_7 python3_8"}
     Homepage:            https://www.gns3.net/
     Description:         Graphical Network Simulator

* net-misc/gns3-server
     Available versions:  (~)2.2.8 {PYTHON_TARGETS="python3_7 python3_8"}
     Homepage:            https://www.gns3.net/
     Description:         GNS3 server to asynchronously manage emulators

Found 2 matches

Goal accomplished, only the gentoo ebuild in the newest available version is now found.